fix: seems like cattrs changed how enums are destructured

Author: joeldodge79

python/looker_sdk/rtl/serialize.py

@@ -138,6 +138,8 @@ def unstructure_hook(api_model):
             del data[key]
         elif value == model.EXPLICIT_NULL:
             data[key] = None
+        elif isinstance(value, enum.Enum):
+            data[key] = value.value
     for reserved in keyword.kwlist:
         if f"{reserved}_" in data:
             data[reserved] = data.pop(f"{reserved}_")