Remove ConversationalPipeline and Conversation object (#31165)

* Remove ConversationalPipeline and Conversation object, as they have been deprecated for some time and are due for removal

* Update not-doctested.txt

* Fix JA and ZH docs

* Fix JA and ZH docs some more

* Fix JA and ZH docs some more

tests/models/marian/test_modeling_flax_marian.py

@@ -311,10 +311,6 @@ class FlaxMarianModelTest(FlaxModelTesterMixin, unittest.TestCase, FlaxGeneratio
             outputs = model(input_ids)
             self.assertIsNotNone(outputs)
 
-    @unittest.skip("Skipping for now, to fix @ArthurZ or @ydshieh")
-    def test_pipeline_conversational(self):
-        pass
-
 
 @require_flax
 @require_sentencepiece

tests/models/marian/test_modeling_marian.py

@@ -248,7 +248,6 @@ class MarianModelTest(ModelTesterMixin, GenerationTesterMixin, PipelineTesterMix
     all_generative_model_classes = (MarianMTModel,) if is_torch_available() else ()
     pipeline_model_mapping = (
         {
-            "conversational": MarianMTModel,
             "feature-extraction": MarianModel,
             "summarization": MarianMTModel,
             "text-generation": MarianForCausalLM,
@@ -350,10 +349,6 @@ class MarianModelTest(ModelTesterMixin, GenerationTesterMixin, PipelineTesterMix
     def test_tie_word_embeddings_decoder(self):
         pass
 
-    @unittest.skip("Skipping for now, to fix @ArthurZ or @ydshieh")
-    def test_pipeline_conversational(self):
-        pass
-
     @unittest.skip(
         reason="This architecure seem to not compute gradients properly when using GC, check: https://github.com/huggingface/transformers/pull/27124"
     )

tests/models/marian/test_modeling_tf_marian.py

@@ -184,7 +184,6 @@ class TFMarianModelTest(TFModelTesterMixin, PipelineTesterMixin, unittest.TestCa
     all_generative_model_classes = (TFMarianMTModel,) if is_tf_available() else ()
     pipeline_model_mapping = (
         {
-            "conversational": TFMarianMTModel,
             "feature-extraction": TFMarianModel,
             "summarization": TFMarianMTModel,
             "text2text-generation": TFMarianMTModel,
@@ -208,10 +207,6 @@ class TFMarianModelTest(TFModelTesterMixin, PipelineTesterMixin, unittest.TestCa
         config_and_inputs = self.model_tester.prepare_config_and_inputs_for_common()
         self.model_tester.check_decoder_model_past_large_inputs(*config_and_inputs)
 
-    @unittest.skip("Skipping for now, to fix @ArthurZ or @ydshieh")
-    def test_pipeline_conversational(self):
-        pass
-
 
 @require_tf
 class AbstractMarianIntegrationTest(unittest.TestCase):