fix(grpc): handle NotImplementedError from add_done_callback in aio client

[cschanhniem]

Fixes #4429

Problem

When a user interceptor awaits a grpc.aio call object, some interceptors wrap it in a type that does not implement add_done_callback. This causes a NotImplementedError that is not caught, leaving spans unfinished.

Solution

Catch NotImplementedError from call.add_done_callback() and invoke the callback immediately since code and details are already known at that point.

Changes

• Wrap call.add_done_callback() in a try/except for NotImplementedError in _wrap_unary_response
• When caught, call the callback immediately with the call object
• Apply ruff formatting to changed files
• Add test verifying the fallback behavior

Original PR: #4429 by @alliasgher

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: cschanhniem / name: j (1b52567, 97e115c, 9c1b56d, bfce730)

[github-actions]

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