Add TFConvNextModel (#15750)

* feat: initial implementation of convnext in tensorflow.

* fix: sample code for the classification model.

* chore: added checked for  from the classification model.

* chore: set bias initializer in the classification head.

* chore: updated license terms.

* chore: removed ununsed imports

* feat: enabled  argument during using drop_path.

* chore: replaced tf.identity with layers.Activation(linear).

* chore: edited default checkpoint.

* fix: minor bugs in the initializations.

* partial-fix: tf model errors for loading pretrained pt weights.

* partial-fix: call method updated

* partial-fix: cross loading of weights (4x3 variables to be matched)

* chore: removed unneeded comment.

* removed playground.py

* rebasing

* rebasing and removing playground.py.

* fix: renaming TFConvNextStage conv and layer norm layers

* chore: added initializers and other minor additions.

* chore: added initializers and other minor additions.

* add: tests for convnext.

* fix: integration tester class.

* fix: issues mentioned in pr feedback (round 1).

* fix: how output_hidden_states arg is propoagated inside the network.

* feat: handling of  arg for pure cnn models.

* chore: added a note on equal contribution in model docs.

* rebasing

* rebasing and removing playground.py.

* feat: encapsulation for the convnext trunk.

* Fix variable naming; Test-related corrections; Run make fixup

* chore: added Joao as a contributor to convnext.

* rebasing

* rebasing and removing playground.py.

* rebasing

* rebasing and removing playground.py.

* chore: corrected copyright year and added comment on NHWC.

* chore: fixed the black version and ran formatting.

* chore: ran make style.

* chore: removed from_pt argument from test, ran make style.

* rebasing

* rebasing and removing playground.py.

* rebasing

* rebasing and removing playground.py.

* fix: tests in the convnext subclass, ran make style.

* rebasing

* rebasing and removing playground.py.

* rebasing

* rebasing and removing playground.py.

* chore: moved convnext test to the correct location

* fix: locations for the test file of convnext.

* fix: convnext tests.

* chore: applied  sgugger's suggestion for dealing w/ output_attentions.

* chore: added comments.

* chore: applied updated quality enviornment style.

* chore: applied formatting with quality enviornment.

* chore: revert to the previous tests/test_modeling_common.py.

* chore: revert to the original test_modeling_common.py

* chore: revert to previous states for test_modeling_tf_common.py and modeling_tf_utils.py

* fix: tests for convnext.

* chore: removed output_attentions argument from convnext config.

* chore: revert to the earlier tf utils.

* fix: output shapes of the hidden states

* chore: removed unnecessary comment

* chore: reverting to the right test_modeling_tf_common.py.

* Styling nits

Co-authored-by: ariG23498 <aritra.born2fly@gmail.com>
Co-authored-by: Joao Gante <joao@huggingface.co>
Co-authored-by: Sylvain Gugger <Sylvain.gugger@gmail.com>

tests/test_modeling_tf_common.py

@@ -474,8 +474,8 @@ class TFModelTesterMixin:
                     ),
                     "input_ids": tf.keras.Input(batch_shape=(2, max_input), name="input_ids", dtype="int32"),
                 }
-            # TODO: A better way to handle vision models
-            elif model_class.__name__ in ["TFViTModel", "TFViTForImageClassification", "TFCLIPVisionModel"]:
+            # `pixel_values` implies that the input is an image
+            elif model_class.main_input_name == "pixel_values":
                 inputs = tf.keras.Input(
                     batch_shape=(
                         3,