Mark pipeline tests to skip them easily (#21887)

* Mark pipeline tests to skip them easily

* Mark the mixin as pipeline test

* Update src/transformers/testing_utils.py

Co-authored-by: Yih-Dar <2521628+ydshieh@users.noreply.github.com>

---------

Co-authored-by: Yih-Dar <2521628+ydshieh@users.noreply.github.com>

tests/pipelines/test_pipelines_object_detection.py

@@ -23,6 +23,7 @@ from transformers import (
     pipeline,
 )
 from transformers.testing_utils import (
+    is_pipeline_test,
     nested_simplify,
     require_pytesseract,
     require_tf,
@@ -45,6 +46,7 @@ else:
             pass
 
 
+@is_pipeline_test
 @require_vision
 @require_timm
 @require_torch