fireworks[minor]: remove default model and temperature (#30965)

`mixtral-8x-7b-instruct` was recently retired from Fireworks Serverless.

Here we remove the default model altogether, so that the model must be
explicitly specified on init:
```python
ChatFireworks(model="accounts/fireworks/models/llama-v3p1-70b-instruct")  # for example
```

We also set a null default for `temperature`, which previously defaulted
to 0.0. This parameter will no longer be included in request payloads
unless it is explicitly provided.

libs/partners/fireworks/tests/integration_tests/test_chat_models.py

@@ -13,54 +13,13 @@ from typing_extensions import TypedDict
 
 from langchain_fireworks import ChatFireworks
 
-
-def test_chat_fireworks_call() -> None:
-    """Test valid call to fireworks."""
-    llm = ChatFireworks(  # type: ignore[call-arg]
-        model="accounts/fireworks/models/llama-v3p1-70b-instruct", temperature=0
-    )
-
-    resp = llm.invoke("Hello!")
-    assert isinstance(resp, AIMessage)
-
-    assert len(resp.content) > 0
-
-
-def test_tool_choice() -> None:
-    """Test that tool choice is respected."""
-    llm = ChatFireworks(  # type: ignore[call-arg]
-        model="accounts/fireworks/models/llama-v3p1-70b-instruct", temperature=0
-    )
-
-    class MyTool(BaseModel):
-        name: str
-        age: int
-
-    with_tool = llm.bind_tools([MyTool], tool_choice="MyTool")
-
-    resp = with_tool.invoke("Who was the 27 year old named Erick?")
-    assert isinstance(resp, AIMessage)
-    assert resp.content == ""  # should just be tool call
-    tool_calls = resp.additional_kwargs["tool_calls"]
-    assert len(tool_calls) == 1
-    tool_call = tool_calls[0]
-    assert tool_call["function"]["name"] == "MyTool"
-    assert json.loads(tool_call["function"]["arguments"]) == {
-        "age": 27,
-        "name": "Erick",
-    }
-    assert tool_call["type"] == "function"
-    assert isinstance(resp.tool_calls, list)
-    assert len(resp.tool_calls) == 1
-    tool_call = resp.tool_calls[0]
-    assert tool_call["name"] == "MyTool"
-    assert tool_call["args"] == {"age": 27, "name": "Erick"}
+_MODEL = "accounts/fireworks/models/llama-v3p1-8b-instruct"
 
 
 def test_tool_choice_bool() -> None:
     """Test that tool choice is respected just passing in True."""
 
-    llm = ChatFireworks(  # type: ignore[call-arg]
+    llm = ChatFireworks(
         model="accounts/fireworks/models/llama-v3p1-70b-instruct", temperature=0
     )
 
@@ -84,17 +43,9 @@ def test_tool_choice_bool() -> None:
     assert tool_call["type"] == "function"
 
 
-def test_stream() -> None:
-    """Test streaming tokens from ChatFireworks."""
-    llm = ChatFireworks()  # type: ignore[call-arg]
-
-    for token in llm.stream("I'm Pickle Rick"):
-        assert isinstance(token.content, str)
-
-
 async def test_astream() -> None:
     """Test streaming tokens from ChatFireworks."""
-    llm = ChatFireworks()  # type: ignore[call-arg]
+    llm = ChatFireworks(model=_MODEL)
 
     full: Optional[BaseMessageChunk] = None
     chunks_with_token_counts = 0
@@ -125,18 +76,9 @@ async def test_astream() -> None:
     assert full.response_metadata["model_name"]
 
 
-async def test_abatch() -> None:
-    """Test abatch tokens from ChatFireworks."""
-    llm = ChatFireworks()  # type: ignore[call-arg]
-
-    result = await llm.abatch(["I'm Pickle Rick", "I'm not Pickle Rick"])
-    for token in result:
-        assert isinstance(token.content, str)
-
-
 async def test_abatch_tags() -> None:
     """Test batch tokens from ChatFireworks."""
-    llm = ChatFireworks()  # type: ignore[call-arg]
+    llm = ChatFireworks(model=_MODEL)
 
     result = await llm.abatch(
         ["I'm Pickle Rick", "I'm not Pickle Rick"], config={"tags": ["foo"]}
@@ -145,18 +87,9 @@ async def test_abatch_tags() -> None:
         assert isinstance(token.content, str)
 
 
-def test_batch() -> None:
-    """Test batch tokens from ChatFireworks."""
-    llm = ChatFireworks()  # type: ignore[call-arg]
-
-    result = llm.batch(["I'm Pickle Rick", "I'm not Pickle Rick"])
-    for token in result:
-        assert isinstance(token.content, str)
-
-
 async def test_ainvoke() -> None:
     """Test invoke tokens from ChatFireworks."""
-    llm = ChatFireworks()  # type: ignore[call-arg]
+    llm = ChatFireworks(model=_MODEL)
 
     result = await llm.ainvoke("I'm Pickle Rick", config={"tags": ["foo"]})
     assert isinstance(result.content, str)
@@ -164,7 +97,7 @@ async def test_ainvoke() -> None:
 
 def test_invoke() -> None:
     """Test invoke tokens from ChatFireworks."""
-    llm = ChatFireworks()  # type: ignore[call-arg]
+    llm = ChatFireworks(model=_MODEL)
 
     result = llm.invoke("I'm Pickle Rick", config=dict(tags=["foo"]))
     assert isinstance(result.content, str)