Fix type annotation of UUID

According to mypy the previous annotation violated the LSP.
Therefore, we use the types of the supertype method and check for
correct types in the method.

portal/model/Uuid.py

@@ -26,12 +26,12 @@ class Uuid(types.TypeDecorator):
     def load_dialect_impl(self, dialect: Dialect) -> types.TypeEngine[Any]:
         return types.String(UUID_LENGTH)
 
-    def process_bind_param(self, value: str | UUID, dialect: Dialect) -> Optional[str]:
+    def process_bind_param(self, value: Any | None, dialect: Dialect) -> Optional[str]:
         if isinstance(value, str):
             # Manually create UUID from string, to raise an error if the string is malformed
             UUID(value)
 
-        return str(value) if value else None
+        return str(value) if isinstance(value, UUID) else None
 
     def process_result_value(
         self, value: Optional[str], dialect: Dialect