Send max_patch_bytes to Gitaly via Gitaly::CommitDiffRequest

What does this MR do?

Sends MaxPatchBytes to Gitaly via Gitaly::CommitDiffRequest.

We used to apply this limitation on GitLab when using Rugged. Now that we've shifted to Gitaly, this parameter needs to be sent via a RPC request.

MRs:

• gitaly!880 (merged)
• gitaly-proto!223 (merged)

What are the relevant issue numbers?

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/50635

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides