chore: further constraint RPC max message size

[jon-whit]

Description

This sets stricter RPC message size limits on the OpenFGA gRPC server. Existing API definitions have strict limits on resource inputs and so the default 4MB gRPC message size limit is overly generous. Additionally, request context added for ABAC support is ultimately constrained by the RPC message size limit, and so setting a stricter limit on it is important to constrain the arbitrary request context that can be provided.

I've also bumped up to the most recent protobuf API changes that were made in openfga/api#125

References

#1192

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

[jon-whit]

• todo: add a server level test for this

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (c01b461) 82.26% compared to head (e0ff047) 82.29%.

❗ Current head e0ff047 differs from pull request most recent head a54ff4a. Consider uploading reports for the commit a54ff4a to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1222      +/-   ##
==========================================
+ Coverage   82.26%   82.29%   +0.04%     
==========================================
  Files          83       83              
  Lines        9555     9557       +2     
==========================================
+ Hits         7859     7864       +5     
+ Misses       1342     1340       -2     
+ Partials      354      353       -1     

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