Don't mutate config in the check_config helper (home-assistant#104241)

Author: emontnemery

homeassistant/helpers/check_config.py

@@ -232,10 +232,10 @@ async def _get_integration(
         config_schema = getattr(component, "CONFIG_SCHEMA", None)
         if config_schema is not None:
             try:
-                config = config_schema(config)
+                validated_config = config_schema(config)
                 # Don't fail if the validator removed the domain from the config
-                if domain in config:
-                    result[domain] = config[domain]
+                if domain in validated_config:
+                    result[domain] = validated_config[domain]
             except vol.Invalid as ex:
                 _comp_error(ex, domain, config, config[domain])
                 continue