Python: Include Bing Grounding Tool call results in invoke_stream responses (#12265)

### Motivation and Context

According to the [Terms of Service for Grounding with Bing
Search](https://www.microsoft.com/en-us/bing/apis/grounding-legal#use-and-display-requirements),
the tool’s call results must be displayed in their original format.
Currently, in the `AzureAIAgent` `invoke/invoke_stream` responses,
search results are included in the `AnnotationContent`, but the search
query itself is not.
This PR updates the response of `invoke/invoke_stream` to include the
Bing Grounding Tool’s call results, so that the Bing search query can
also be displayed.

### Description

- Fixe an issue where errors occurred when handling Bing Grounding Tool
results in streaming mode
- Update `invoke/invoke_stream` responses to include the Bing Grounding
Tool call results

### Contribution Checklist

<!-- Before submitting this PR, please make sure: -->

- [x] The code builds clean without any errors or warnings
- [x] The PR follows the [SK Contribution
Guidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
and the [pre-submission formatting
script](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [x] All unit tests pass, and I have added new tests where possible
- [x] I didn't break anyone 😄

---------

Co-authored-by: Evan Mattson <35585003+moonbox3@users.noreply.github.com>

Author: KanchiShimono

python/semantic_kernel/agents/azure_ai/agent_content_generation.py

@@ -398,14 +398,13 @@ def generate_streaming_bing_grounding_content(
 
     for index, tool in enumerate(step_details.tool_calls):
         if tool.type == "bing_grounding":
-            bing_tool = cast(RunStepBingGroundingToolCall, tool)
-            arguments = getattr(bing_tool, "bing_grounding", None)
+            arguments = tool.get("bing_grounding", None)
             items.append(
                 FunctionCallContent(
-                    id=bing_tool.id,
+                    id=tool.id,
                     index=index,
-                    name=bing_tool.type,
-                    function_name=bing_tool.type,
+                    name=tool.type,
+                    function_name=tool.type,
                     arguments=arguments,
                 )
             )