Mistral-related models for QnA (#34045)

* mistral qna start

* mixtral qna

* oops

* qwen2 qna

* qwen2moe qna

* add missing input embed methods

* add copied to all methods, can't directly from llama due to the prefix

* make top level copied from

tests/models/qwen2/test_modeling_qwen2.py

@@ -43,6 +43,7 @@ if is_torch_available():
 
     from transformers import (
         Qwen2ForCausalLM,
+        Qwen2ForQuestionAnswering,
         Qwen2ForSequenceClassification,
         Qwen2ForTokenClassification,
         Qwen2Model,
@@ -300,7 +301,13 @@ class Qwen2ModelTester:
 # Copied from tests.models.mistral.test_modeling_mistral.MistralModelTest with Mistral->Qwen2
 class Qwen2ModelTest(ModelTesterMixin, GenerationTesterMixin, PipelineTesterMixin, unittest.TestCase):
     all_model_classes = (
-        (Qwen2Model, Qwen2ForCausalLM, Qwen2ForSequenceClassification, Qwen2ForTokenClassification)
+        (
+            Qwen2Model,
+            Qwen2ForCausalLM,
+            Qwen2ForSequenceClassification,
+            Qwen2ForTokenClassification,
+            Qwen2ForQuestionAnswering,
+        )
         if is_torch_available()
         else ()
     )
@@ -312,6 +319,7 @@ class Qwen2ModelTest(ModelTesterMixin, GenerationTesterMixin, PipelineTesterMixi
             "token-classification": Qwen2ForTokenClassification,
             "text-generation": Qwen2ForCausalLM,
             "zero-shot": Qwen2ForSequenceClassification,
+            "question-answering": Qwen2ForQuestionAnswering,
         }
         if is_torch_available()
         else {}