feat: support assertions with context and contextual tuples

[ewanharris]

Description

Adds Context and ContextualTuples support to Assertions in the OpenFGAClient

References

openfga/sdk-generator#449
openfga/api#185

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

All modified and coverable lines are covered by tests ✅

Project coverage is 25.78%. Comparing base (389d645) to head (946c053).

❌ Your project status has failed because the head coverage (25.78%) is below the target coverage (80.00%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #169      +/-   ##
==========================================
+ Coverage   25.73%   25.78%   +0.04%     
==========================================
  Files         104      104              
  Lines       12585    12593       +8     
==========================================
+ Hits         3239     3247       +8     
  Misses       9075     9075              
  Partials      271      271              

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[aaguiarz]

If it looks good to Ewan it looks good to me :)