Fix unsafe websocket stop call in isy994 (#71071)
Fix unsafe websocket stop call in isy994 (#71071)

Fixes
```
2022-04-29 12:49:10 ERROR (MainThread) [homeassistant.config_entries] Error unloading entry Alexander (192.168.209.83) for isy994
Traceback (most recent call last):
  File "/Users/bdraco/home-assistant/homeassistant/config_entries.py", line 474, in async_unload
    result = await component.async_unload_entry(hass, self)
  File "/Users/bdraco/home-assistant/homeassistant/components/isy994/__init__.py", line 294, in async_unload_entry
    await hass.async_add_executor_job(_stop_auto_update)
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/concurrent/futures/thread.py", line 58, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/Users/bdraco/home-assistant/homeassistant/components/isy994/__init__.py", line 292, in _stop_auto_update
    isy.websocket.stop()
  File "/Users/bdraco/home-assistant/venv/lib/python3.9/site-packages/pyisy/events/websocket.py", line 110, in stop
    self.websocket_task.cancel()
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/asyncio/base_events.py", line 753, in call_soon
    self._check_thread()
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/asyncio/base_events.py", line 790, in _check_thread
    raise RuntimeError(
RuntimeError: Non-thread-safe operation invoked on an event loop other than the current one
```
nkgilley/home-assistant,mezz64/home-assistant,w1ll1am23/home-assistant,toddeye/home-assistant,w1ll1am23/home-assistant,nkgilley/home-assistant,mezz64/home-assistant,toddeye/home-assistant