feat: Feature - add python optional dependencies/extras support

[MarcusArdelean]

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What does this PR do?

PEP 508 brought optional dependencies or extras, enabling developers to include supplementary dependencies in their packages, which were installed only when necessary. This PR includes the required changes to support the optional dependencies syntax.

Where should the reviewer start?

Python CLI optional dependencies pitch
snyk-python-plugin PR

Any background context you want to provide?

Until now, Snyk Python CLI didn't support at all the optional dependencies/extras syntax, so all graph creation requests (snyk test command for example) failed.

What are the relevant tickets?

Support ticket SUP-2224