fix(test): use real ActionValidators instance in model serving processor fixtures

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: fregataa

tests/component/model_serving/conftest.py

@@ -7,6 +7,7 @@
 from ai.backend.common.bgtask.bgtask import BackgroundTaskManager
 from ai.backend.common.events.hub.hub import EventHub
 from ai.backend.manager.actions.validators import ActionValidators
+from ai.backend.manager.actions.validators.rbac import RBACValidators
 from ai.backend.manager.api.rest.routing import RouteRegistry
 from ai.backend.manager.api.rest.service.handler import ServiceHandler
 from ai.backend.manager.api.rest.service.registry import register_service_routes
@@ -68,7 +69,9 @@ def model_serving_processors(
         revision_generator_registry=revision_gen,
     )
     return ModelServingProcessors(
-        service=service, action_monitors=[], validators=MagicMock(spec=ActionValidators)
+        service=service,
+        action_monitors=[],
+        validators=ActionValidators(rbac=MagicMock(spec=RBACValidators)),
     )