Fix async bulk failures

[pquentin]

I'm seeing weird timeout issues in Buildkite with async bulk API in Python 3.9/3.10. See the following build for example: https://buildkite.com/elastic/elasticsearch-serverless-python-rest-tests/builds/695.

Python 3.9 (twice):

2024-06-19 15:01:57 RT	=========================== short test summary info ============================
2024-06-19 15:01:57 RT	FAILED test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestStreamingBulk::test_all_documents_get_inserted - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:57 RT	FAILED test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestStreamingBulk::test_documents_data_types - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:57 RT	FAILED test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestBulk::test_all_documents_get_inserted - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:57 RT	FAILED test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestBulk::test_stats_only_reports_numbers - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:57 RT	FAILED test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestScan::test_order_can_be_preserved - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:57 RT	FAILED test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestScan::test_all_documents_are_read - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:57 RT	ERROR test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestReindex::test_reindex_passes_kwargs_to_scan_and_bulk - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:57 RT	ERROR test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestReindex::test_reindex_accepts_a_query - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:57 RT	ERROR test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestReindex::test_all_documents_get_moved - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:57 RT	ERROR test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestAsyncDataStreamReindex::test_reindex_index_datastream[None] - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:57 RT	ERROR test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestAsyncDataStreamReindex::test_reindex_index_datastream[create] - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:57 RT	ERROR test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestAsyncDataStreamReindex::test_reindex_index_datastream_op_type_index - elastic_transport.ConnectionTimeout: Connection timed out

Python 3.10 (twice):

2024-06-19 15:01:47 RT	FAILED test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestStreamingBulk::test_all_documents_get_inserted - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:47 RT	FAILED test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestStreamingBulk::test_documents_data_types - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:47 RT	FAILED test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestBulk::test_all_documents_get_inserted - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:47 RT	FAILED test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestBulk::test_stats_only_reports_numbers - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:47 RT	FAILED test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestScan::test_order_can_be_preserved - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:47 RT	FAILED test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestScan::test_all_documents_are_read - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:47 RT	ERROR test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestReindex::test_reindex_passes_kwargs_to_scan_and_bulk - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:47 RT	ERROR test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestReindex::test_reindex_accepts_a_query - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:47 RT	ERROR test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestReindex::test_all_documents_get_moved - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:47 RT	ERROR test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestAsyncDataStreamReindex::test_reindex_index_datastream[None] - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:47 RT	ERROR test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestAsyncDataStreamReindex::test_reindex_index_datastream[create] - elastic_transport.ConnectionTimeout: Connection timed out
2024-06-19 15:01:47 RT	ERROR test_elasticsearch_serverless/test_async/test_server/test_helpers.py::TestAsyncDataStreamReindex::test_reindex_index_datastream_op_type_index - elastic_transport.ConnectionTimeout: Connection timed out

I have tried setting the timeout to 1 minute, and it still fails. This is very mysterious. I'll have to mark those commands as xfail for now.