feat: Implement the 'max_tool_calls' parameter for the Responses API (#4062)

# Problem
Responses API uses max_tool_calls parameter to limit the number of tool
calls that can be generated in a response. Currently, LLS implementation
of the Responses API does not support this parameter.

# What does this PR do?
This pull request adds the max_tool_calls field to the response object
definition and updates the inline provider. it also ensures that:

- the total number of calls to built-in and mcp tools do not exceed
max_tool_calls
- an error is thrown if max_tool_calls < 1 (behavior seen with the
OpenAI Responses API, but we can change this if needed)

Closes #[3563](https://github.com/llamastack/llama-stack/issues/3563)

## Test Plan
- Tested manually for change in model response w.r.t supplied
max_tool_calls field.
- Added integration tests to test invalid max_tool_calls parameter.
- Added integration tests to check max_tool_calls parameter with
built-in and function tools.
- Added integration tests to check max_tool_calls parameter in the
returned response object.
- Recorded OpenAI Responses API behavior using a sample script:
https://github.com/s-akhtar-baig/llama-stack-examples/blob/main/responses/src/max_tool_calls.py

Co-authored-by: Ashwin Bharambe <ashwin.bharambe@gmail.com>

src/llama_stack/apis/agents/openai_responses.py

@@ -594,6 +594,7 @@ class OpenAIResponseObject(BaseModel):
     :param truncation: (Optional) Truncation strategy applied to the response
     :param usage: (Optional) Token usage information for the response
     :param instructions: (Optional) System message inserted into the model's context
+    :param max_tool_calls: (Optional) Max number of total calls to built-in tools that can be processed in a response
     """
 
     created_at: int
@@ -615,6 +616,7 @@ class OpenAIResponseObject(BaseModel):
     truncation: str | None = None
     usage: OpenAIResponseUsage | None = None
     instructions: str | None = None
+    max_tool_calls: int | None = None
 
 
 @json_schema_type