Fix: Bug in Optional of GenericType

[ncilfone]

What does this PR do?

fixed bug in allowing inherited GenericType to be optional. since the typing.Optional annotation is stripped off of the parents we needed to pass on the optional metadata to override the typing check.

Checklist

• [x] Did you adhere to PEP-8 standards?
• [x] Did you run black and isort prior to submitting your PR?
• [x] Does your PR pass all existing unit tests?
• [x] Did you add associated unit tests for any additional functionality?
• [x] Did you provide code documentation (Google Docstring format) whenever possible, even for simple functions or classes?
• [x] Did you add necessary documentation to the website?

Review

Request will go to reviewers to approve for merge.

[coveralls]

Pull Request Test Coverage Report for Build 3989948748

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 10 of 10 (100.0%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.1%) to 95.177%

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Totals
Change from base Build 3959887721:	0.1%
Covered Lines:	2526
Relevant Lines:	2654

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💛 - Coveralls