Update dapr/actor/runtime/mock_state_manager.py

Fixing bug in try_add_state as mentioned in PR #756

Co-authored-by: Elena Kolevska <[email protected]>
Signed-off-by: Lorenzo Curcio <[email protected]>

Author: lor1113

dapr/actor/runtime/mock_state_manager.py

@@ -51,7 +51,7 @@ async def try_add_state(self, state_name: str, value: T) -> bool:
                 return True
             return False
         existed = state_name in self._mock_state
-        if not existed:
+        if existed:
             return False
         self._default_state_change_tracker[state_name] = StateMetadata(value, StateChangeKind.add)
         self._mock_state[state_name] = value