feat: support contextual_tuples in expand requests

[evansims]

Description

This PR adds support for contextual_tuples in expand requests. (It follows up with support for auto-generated changes already included in a previous commit, #163.)

References

• feat(python-sdk): support contextual_tuples in expand requests sdk-generator#473
• openfga/js-sdk@bfd4679

Review Checklist

• I have clicked on "allow edits by maintainers".
• I have added documentation for new/changed functionality in this PR or in a PR to openfga.dev [Provide a link to any relevant PRs in the references section above]
• The correct base branch is being used, if not main
• I have added tests to validate that the change in functionality is working as expected

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 73.68421% with 5 lines in your changes missing coverage. Please review.

Project coverage is 69.56%. Comparing base (626939b) to head (17730f0).

Files with missing lines	Patch %	Lines
openfga_sdk/client/models/expand_request.py	80.00%	3 Missing ⚠️
openfga_sdk/client/client.py	50.00%	1 Missing ⚠️
openfga_sdk/sync/client/client.py	50.00%	1 Missing ⚠️

Additional details and impacted files

@@ Coverage Diff @@## main #164 +/- ##
=======================================
Coverage 69.56% 69.56% =======================================
Files 135 135 Lines 10839 10857 +18 =======================================
+ Hits 7540 7553 +13 - Misses 3299 3304 +5 

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[jimmyjames]

Any opportunity to add some (useful/meaningful) tests for this change?

[evansims]

Any opportunity to add some (useful/meaningful) tests for this change?

@jimmyjames I don't think there'd be much benefit in this specific case, but I do have a follow-up PR I'm preparing (after 0.9.1. release) that includes a significantly reworked/expanded test suite and some proper integration tests for all endpoints. If you're OK with deferring the test coverage for a few, I'll include that in the follow-up PR.