fix: simplify value retrieval in EnumField by removing unnecessary check for 'value' attribute

Author: gabino

mongoengine_plus/types/enum_field.py

@@ -19,7 +19,7 @@ def __init__(self, enum: Type[Enum], *args, **kwargs):
         super(EnumField, self).__init__(*args, **kwargs)
 
     def __get_value(self, enum: Enum) -> str:
-        return enum.value if hasattr(enum, 'value') else str(enum)
+        return enum.value
 
     def to_python(self, value: Enum) -> Enum:  # pragma: no cover
         return self.enum(super(EnumField, self).to_python(value))