Avoid trying to import platforms that do not exist (#112028)

* Avoid trying to import platforms that do not exist

* adjust

* fixes

* cleanup

* cleanup

* cleanup

* Apply suggestions from code review

* docs

* fixes

* fixes

* comment

* coverage

* coverage

* coverage

* Switch config to use async_get_component

This was another path where integrations that were marked to load in the executor
would be loaded in the loop

* Switch config to use async_get_component/async_get_platform

This was another path where integrations that were marked to load in the executor
would be loaded in the loop

* merge

* refactor

* refactor

* coverage

* preen

* preen

homeassistant/helpers/integration_platform.py

@@ -48,6 +48,10 @@ def _get_platform(
         )
         return None
 
+    if integration.platform_exists(platform_name) is False:
+        # If the platform cannot possibly exist, don't bother trying to load it
+        return None
+
     try:
         return integration.get_platform(platform_name)
     except ImportError as err: