Align valid_entity_id with new slugify (#20231)

* slug

* ensure a dot

* fix

* schema_with_slug_keys

* lint

* test

homeassistant/helpers/config_validation.py

@@ -319,7 +319,23 @@ def service(value):
                       .format(value))
 
 
-def slug(value):
+def schema_with_slug_keys(value_schema: Union[T, Callable]) -> Callable:
+    """Ensure dicts have slugs as keys.
+
+    Replacement of vol.Schema({cv.slug: value_schema}) to prevent misleading
+    "Extra keys" errors from voluptuous.
+    """
+    schema = vol.Schema({str: value_schema})
+
+    def verify(value: Dict) -> Dict:
+        """Validate all keys are slugs and then the value_schema."""
+        for key in value.keys():
+            slug(key)
+        return schema(value)
+    return verify
+
+
+def slug(value: Any) -> str:
     """Validate value is a valid slug."""
     if value is None:
         raise vol.Invalid('Slug should not be None')
@@ -330,7 +346,7 @@ def slug(value):
     raise vol.Invalid('invalid slug {} (try {})'.format(value, slg))
 
 
-def slugify(value):
+def slugify(value: Any) -> str:
     """Coerce a value to a slug."""
     if value is None:
         raise vol.Invalid('Slug should not be None')