remove typing_extension dependency

kierandidi commented 3 months ago

Reference Issues/PRs

What does this implement/fix? Explain your changes

Remove typing_extension as a dependency since we now only support Python >=3.8 and Literal is included in typing there. Use try catch block to still use typing_extension if user has Python3.7 and manually installs it

What testing did you do to verify the changes in this PR?

Ran pytests.

Pull Request Checklist

[x] Added a note about the modification or contribution to the ./CHANGELOG.md file (if applicable)
[ ] Added appropriate unit test functions in the ./graphein/tests/* directories (if applicable)
[ ] Modify documentation in the corresponding Jupyter Notebook under ./notebooks/ (if applicable)
[ ] Ran python -m py.test tests/ and make sure that all unit tests pass (for small modifications, it might be sufficient to only run the specific test file, e.g., python -m py.test tests/protein/test_graphs.py)
[ ] Checked for style issues by running black . and isort .