Revert "get first enum automatically, but ofc mypy doesn't pick up the new metaclass so can't use :("

This reverts commit bb28b228be.

selfdrive/car/data_structures.py

@@ -28,15 +28,7 @@ def apply_auto_fields(cls=None, /, **kwargs):
   return cls
 
 
-class EnumMeta(EnumType):
-  def __call__(cls, value=None, **kwargs):
-    # Return first enum if value is None
-    if value is None:
-      value = next(iter(cls))
-    return super().__call__(value, **kwargs)
-
-
-class StrEnum(_StrEnum, metaclass=EnumMeta):
+class StrEnum(_StrEnum):
   @staticmethod
   def _generate_next_value_(name, *args):
     # auto() defaults to name.lower()