Fix python sys.path collecting algorithm

[tamarinvs19]

Description

Now we collect only parent directory of top level module for sys.path. For example, if import is import a.b.c we add only one path to module a.

Fixes #1827

How to test

Manual tests

See #1827. Now we cannot generate real tests for this class, but we don't fail.

Note: Because of langchain project is large, loading information about types is very long!

Self-check list

Check off the item if the statement is true. Hint: [x] is a marked item.

Please do not delete the list or its items.

• I've set the proper labels for my PR (at least, for category and component).
• PR title and description are clear and intelligible.
• I've added enough comments to my code, particularly in hard-to-understand areas.
• The functionality I've repaired, changed or added is covered with automated tests.
• Manual tests have been provided optionally.
• The documentation for the functionality I've been working on is up-to-date.