fix: Syntax error with missing stubs at the end of some function calls (#2116)

# What does this PR do?
This PR adds stubs to the end of functions create_agent_turn,
create_openai_response and job_result.

[//]: # (If resolving an issue, uncomment and update the line below)
[//]: # (Closes #[issue-number])

## Test Plan
Ran provided unit tests

[//]: # (## Documentation)

llama_stack/apis/agents/agents.py

@@ -415,6 +415,7 @@ class Agents(Protocol):
         :returns: If stream=False, returns a Turn object.
                   If stream=True, returns an SSE event stream of AgentTurnResponseStreamChunk
         """
+        ...
 
     @webmethod(
         route="/agents/{agent_id}/session/{session_id}/turn/{turn_id}/resume",
@@ -606,3 +607,4 @@ class Agents(Protocol):
         :param model: The underlying LLM used for completions.
         :param previous_response_id: (Optional) if specified, the new response will be a continuation of the previous response. This can be used to easily fork-off new responses from existing responses.
         """
+        ...

llama_stack/apis/eval/eval.py

@@ -95,6 +95,7 @@ class Eval(Protocol):
         :param benchmark_config: The configuration for the benchmark.
         :return: The job that was created to run the evaluation.
         """
+        ...
 
     @webmethod(route="/eval/benchmarks/{benchmark_id}/evaluations", method="POST")
     async def evaluate_rows(
@@ -112,6 +113,7 @@ class Eval(Protocol):
         :param benchmark_config: The configuration for the benchmark.
         :return: EvaluateResponse object containing generations and scores
         """
+        ...
 
     @webmethod(route="/eval/benchmarks/{benchmark_id}/jobs/{job_id}", method="GET")
     async def job_status(self, benchmark_id: str, job_id: str) -> Job:
@@ -140,3 +142,4 @@ class Eval(Protocol):
         :param job_id: The ID of the job to get the result of.
         :return: The result of the job.
         """
+        ...