Explicitely log a warning when the helper doesn't support cache

Closes #278 (closed)

arkindex_worker/cache.py

@@ -380,7 +380,7 @@ def unsupported_cache(func):
     def wrapper(self, *args, **kwargs):
         results = func(self, *args, **kwargs)
 
-        if not self.is_read_only and not self.use_cache:
+        if not (self.is_read_only or self.use_cache):
             logger.warning(
                 f"This API helper `{func.__name__}` did not update the cache database"
             )