Fix python sys.path problems

[tamarinvs19]

Description

Fix problems with unnecessary sys.path-s

Fixes #2008

How to test

Manual tests

See #2008

Self-check list

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• I've set the proper labels for my PR (at least, for category and component).
• PR title and description are clear and intelligible.
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• 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.