Add additional Plex test to IGNORE_UNCAUGHT_EXCEPTIONS list

[dmulcahey]

Proposed change

This PR adds an additional Plex test to the ignore uncaught exceptions list to fix dev builds. Currently builds: #33391, #33393, #33395 are failing with this:

request = <SubRequest 'hass' for <Function test_setup_when_certificate_changed[pyloop]>>

    @pytest.fixture
    def hass(loop, hass_storage, request):
        """Fixture to provide a test instance of Home Assistant."""
    
        def exc_handle(loop, context):
            """Handle exceptions by rethrowing them, which will fail the test."""
            exceptions.append(context["exception"])
            orig_exception_handler(loop, context)
    
        exceptions = []
        hass = loop.run_until_complete(async_test_home_assistant(loop))
        orig_exception_handler = loop.get_exception_handler()
        loop.set_exception_handler(exc_handle)
    
        yield hass
    
        loop.run_until_complete(hass.async_stop(force=True))
        for ex in exceptions:
            if (
                request.module.__name__,
                request.function.__name__,
            ) in IGNORE_UNCAUGHT_EXCEPTIONS:
                continue
            if isinstance(ex, ServiceNotFound):
                continue
>           raise ex

tests/conftest.py:107: 


/usr/local/lib/python3.7/concurrent/futures/thread.py:57: in run
    result = self.fn(*self.args, **self.kwargs)
homeassistant/components/plex/__init__.py:199: in close_websocket_session
    websocket.close()
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <plexwebsocket.PlexWebsocket object at 0x7f3a84466ba8>

    def close(self):
        """Close the listening websocket."""
        self._active = False
>       self._current_task.cancel()
E       AttributeError: 'NoneType' object has no attribute 'cancel'

venv/lib/python3.7/site-packages/plexwebsocket.py:156: AttributeError

It looks like a guard is needed around self._current_task.cancel() in close on PlexWebsocket but that is in a lib and would require a lib update.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Example entry for configuration.yaml:

# Example configuration.yaml

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist
• The code has been formatted using Black (black --fast homeassistant tests)
• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io

If the code communicates with devices, web services, or third-party tools:

• The manifest file has all fields filled out correctly.
  Updated and included derived files by running: python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt.
  Updated by running python3 -m script.gen_requirements_all.
• Untested files have been added to .coveragerc.

The integration reached or maintains the following Integration Quality Scale:

• No score or internal
• 🥈 Silver
• 🥇 Gold
• 🏆 Platinum

[jjlawren]

This shouldn't be necessary if #33398 is merged.

[dmulcahey]

Closing in favor of #33398