PytestUnraisableExceptionWarning from asycio client

[ahgraber]

Version: What redis-py and what redis version is the issue happening on?

redis-py 4.3.4, 4.5.3, 4.5.4
redis 7.0.9

Platform: What platform / version? (For example Python 3.5.1 on Windows 7 / Ubuntu 15.10 / Azure)

Python 3.9.16 | packaged by conda-forge
[Clang 14.0.6 ] on darwin 

Occurs in both arm64 and Rosetta amd64 environments.

Description: Description of your issue, stack traces from errors and code that reproduces the issue

When running unit tests on a redis.asyncio.Redis object, I notice I keep getting PytestUnraisableExceptionWarning that is raised because of Redis.del(), as the self.connection attribute was not set due to early failure in the Redis() constructor.

  /Users/me/mambaforge/envs/x86_ds_utils/lib/python3.9/site-packages/_pytest/unraisableexception.py:78: PytestUnraisableExceptionWarning: Exception ignored in: <function Redis.__del__ at 0x17c0919d0>
  
  Traceback (most recent call last):
    File "/Users/me/mambaforge/envs/x86_ds_utils/lib/python3.9/site-packages/redis/asyncio/client.py", line 458, in __del__
      if self.connection is not None:
  AttributeError: 'RedisCache' object has no attribute 'connection'
  
    warnings.warn(pytest.PytestUnraisableExceptionWarning(msg))

This is the same issue as #2660; the fix #2669 did not resolve this particular AttributeError.
The issue is in Redis.__del__() around line 458, where self.connection is not initialized.

[ahgraber]

I have solved this locally by changing the Redis.__del__() method to be:

class Redis:
    # ...
    def __del__(self, _warnings: Any = warnings) -> None:
        if hasattr(self, "connection") and (self.connection is not None):
            _warnings.warn(
                f"Unclosed client session {self!r}", ResourceWarning, source=self
            )
            context = {"client": self, "message": self._DEL_MESSAGE}
            asyncio.get_running_loop().call_exception_handler(context)

I have not opened a PR because I am uncertain if this will cause unintended downstream consequences.