ref(gcp-serverless): Remove setting .__sentry_transaction (#11346)

we shouldn't be setting `res.__sentry_transaction`, opportunity for
memory leaks + users should be able to get correct span from isolation
scope.

Author: AbhiPrasad

packages/google-cloud-serverless/src/gcpfunction/http.ts

@@ -1,7 +1,6 @@
 import {
   SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN,
   SEMANTIC_ATTRIBUTE_SENTRY_SOURCE,
-  Transaction,
   handleCallbackErrors,
   setHttpStatus,
 } from '@sentry/core';
@@ -59,14 +58,6 @@ function _wrapHttpFunction(fn: HttpFunction, options: Partial<WrapperOptions>):
             request: req,
           });
 
-          if (span instanceof Transaction) {
-            // We also set __sentry_transaction on the response so people can grab the transaction there to add
-            // spans to it later.
-            // TODO(v8): Remove this
-            // eslint-disable-next-line @typescript-eslint/no-explicit-any, @typescript-eslint/no-unsafe-member-access
-            (res as any).__sentry_transaction = span;
-          }
-
           // eslint-disable-next-line @typescript-eslint/unbound-method
           const _end = res.end;
           // eslint-disable-next-line @typescript-eslint/no-explicit-any