SIENTIAPDE-1222

Add placeholder class 'Any' in test_model_repository.py and update invalid_cases to use it

- Introduced a new placeholder class 'Any' to be used in test cases.
- Updated the 'invalid_cases' list to replace integer keys with instances of the 'Any' class, enhancing test coverage for key types.

tests/laborious/utils/repository/test_model_repository.py

@@ -33,6 +33,10 @@ metadata = {
 }
 
 
+class Any:
+    pass
+
+
 invalid_cases = [
     (
         {
@@ -53,8 +57,8 @@ invalid_cases = [
     (
         {
             'value': {
-                1: 1,
-                2: 2
+                Any(): 1,
+                Any(): 2
             }
         }
     )