[CLIP] allow loading projection layer in vision and text model (#18962)

* allow loading projection in text and vision model

* begin tests

* finish test for CLIPTextModelTest

* style

* add slow tests

* add new classes for projection heads

* remove with_projection

* add in init

* add in doc

* fix tests

* fix some more tests

* fix copies

* fix docs

* remove leftover from fix-copies

* add the head models in IGNORE_NON_AUTO_CONFIGURED

* fix docstr

* fix tests

* Apply suggestions from code review

Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>

* add docstr for models

Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>

docs/source/en/model_doc/clip.mdx

@@ -125,6 +125,17 @@ This model was contributed by [valhalla](https://huggingface.co/valhalla). The o
 [[autodoc]] CLIPTextModel
     - forward
 
+## CLIPTextModelWithProjection
+
+[[autodoc]] CLIPTextModelWithProjection
+    - forward
+
+## CLIPVisionModelWithProjection
+
+[[autodoc]] CLIPVisionModelWithProjection
+    - forward
+
+
 ## CLIPVisionModel
 
 [[autodoc]] CLIPVisionModel