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/agents.py

@@ -87,6 +87,7 @@ class Agents(Protocol):
                 "List of guardrails to apply during response generation. Guardrails provide safety and content moderation."
             ),
         ] = None,
+        max_tool_calls: int | None = None,
     ) -> OpenAIResponseObject | AsyncIterator[OpenAIResponseObjectStream]:
         """Create a model response.
 
@@ -97,6 +98,7 @@ class Agents(Protocol):
         :param conversation: (Optional) The ID of a conversation to add the response to. Must begin with 'conv_'. Input and output messages will be automatically added to the conversation.
         :param include: (Optional) Additional fields to include in the response.
         :param guardrails: (Optional) List of guardrails to apply during response generation. Can be guardrail IDs (strings) or guardrail specifications.
+        :param max_tool_calls: (Optional) Max number of total calls to built-in tools that can be processed in a response.
         :returns: An OpenAIResponseObject.
         """
         ...