Adds truncate_prompt_tokens param for embeddings creation (#8999)

Signed-off-by: Flavia Beo <flavia.beo@ibm.com>

tests/entrypoints/openai/test_embedding.py

@@ -144,3 +144,64 @@ async def test_batch_base64_embedding(embedding_client: openai.AsyncOpenAI,
         0].embedding
     assert responses_float.data[1].embedding == responses_default.data[
         1].embedding
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    "model_name",
+    [EMBEDDING_MODEL_NAME],
+)
+async def test_single_embedding_truncation(
+        embedding_client: openai.AsyncOpenAI, model_name: str):
+    input_texts = [
+        "Como o Brasil pode fomentar o desenvolvimento de modelos de IA?",
+    ]
+
+    # test single embedding
+    embeddings = await embedding_client.embeddings.create(
+        model=model_name,
+        input=input_texts,
+        extra_body={"truncate_prompt_tokens": 10})
+    assert embeddings.id is not None
+    assert len(embeddings.data) == 1
+    assert len(embeddings.data[0].embedding) == 4096
+    assert embeddings.usage.completion_tokens == 0
+    assert embeddings.usage.prompt_tokens == 10
+    assert embeddings.usage.total_tokens == 10
+
+    input_tokens = [
+        1, 24428, 289, 18341, 26165, 285, 19323, 283, 289, 26789, 3871, 28728,
+        9901, 340, 2229, 385, 340, 315, 28741, 28804, 2
+    ]
+    embeddings = await embedding_client.embeddings.create(
+        model=model_name,
+        input=input_tokens,
+        extra_body={"truncate_prompt_tokens": 10})
+
+    assert embeddings.id is not None
+    assert len(embeddings.data) == 1
+    assert len(embeddings.data[0].embedding) == 4096
+    assert embeddings.usage.completion_tokens == 0
+    assert embeddings.usage.prompt_tokens == 10
+    assert embeddings.usage.total_tokens == 10
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    "model_name",
+    [EMBEDDING_MODEL_NAME],
+)
+async def test_single_embedding_truncation_invalid(
+        embedding_client: openai.AsyncOpenAI, model_name: str):
+    input_texts = [
+        "Como o Brasil pode fomentar o desenvolvimento de modelos de IA?",
+    ]
+
+    with pytest.raises(openai.BadRequestError):
+        embeddings = await embedding_client.embeddings.create(
+            model=model_name,
+            input=input_texts,
+            extra_body={"truncate_prompt_tokens": 8193})
+        assert "error" in embeddings.object
+        assert "truncate_prompt_tokens value is greater than max_model_len. "\
+               "Please, select a smaller truncation size." in embeddings.message