Attn implementation for composite models (#32238)

* first try

* codestyle

* idefics2 is happy

* [run-slow] llava, llava_next, video_llava, vipllava, llava_next_video, idefics, idefics2, kosmos2, fuyu, blip, blip_2, instructblip, instructblipvideo, paligemma

* fix-copies

* [run-slow] llava, llava_next, video_llava, vipllava, llava_next_video, idefics, idefics2, kosmos2, fuyu, blip, blip_2, instructblip, instructblipvideo

* blip-2 needs to init vision from config

* when was this removed O_o

* minor fix

* tests

* this way?

* tests

* model-agnostic code

* codestyle

* add tests for idefics

* modify general test for VLMs

* no generation test for vlm yet!

* no generation test here also

* wanr in VIT-SDPA if output attn

* add more tests

* user can pass dict as attn impl

* repo consistency

* update

* muicgen

* no prints

* forgot speech enc-dec and clip

* how many composite models we have?

* musicgen meelody is same as mudicgen

* +siglip

* fix tests + add some more

* remove idefics custom overriden code

* make idefics2 automappable

* nits

* skip tests

* doctests

* Update src/transformers/models/idefics2/configuration_idefics2.py

Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>

* Update tests/models/clip/test_modeling_clip.py

Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>

* Update tests/models/idefics2/test_modeling_idefics2.py

Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>

* Update tests/models/idefics2/test_modeling_idefics2.py

Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>

* Update src/transformers/configuration_utils.py

Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>

* major update, no need for automap

* clean up

* add FA2 test

* more tests

* style

* skip tests

* why did these started failing now?

* no attributes for FA2 needed

* one tiny test

* address comment about FA2 false warning

* style

* add new models and resolve conflicts

* fix copies

* let it be this way for now, come back tomorrow to review

* some more fixes

* update

* more updates

* update

* fix copies

* style and tests

* another big update

* fix tests

* fix tests

* update

* another update

* fix tests

* fix copies

* fix tests

---------

Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>

tests/models/gemma2/test_modeling_gemma2.py

@@ -88,6 +88,10 @@ class Gemma2ModelTest(GemmaModelTest, unittest.TestCase):
     def test_model_outputs_equivalence(self, **kwargs):
         pass
 
+    @unittest.skip("Gemma2's forcefully disables sdpa due to softcapping")
+    def test_sdpa_can_dispatch_non_composite_models(self):
+        pass
+
     @parameterized.expand([("float16",), ("bfloat16",), ("float32",)])
     @unittest.skip("Gemma2's eager attn/sdpa attn outputs are expected to be different")
     def test_eager_matches_sdpa_inference(self):