[BugFix][Platform] Fix extra function name in final chunk of streaming tool calls (#8178)

### What this PR does / why we need it?

Fix a bug in the GLM tool call parser where the `function.name` field
was incorrectly included in the final (non-first) chunks of streaming
tool calls.

Per OpenAI streaming semantics, `id`, `type`, and `function.name` must
only appear in the **first** chunk for a given tool call index. When
`_create_remaining_args_delta` was called for continuing/finishing
chunks, it was incorrectly reading the function name from
`delta_message.tool_calls` and re-emitting it, causing clients to see a
duplicate/extra function name in the final chunk.

**Root cause**: The original code always looked up the tool call in
`delta_message.tool_calls` to get the name, id, and type — even when
this was not the first chunk being streamed. This caused the function
name to appear again in the final argument-completion chunk.

**Fix**:
- Track whether arguments have already been streamed
(`already_streamed_args`) for each tool call index.
- Only populate `fallback_tool_call_id`, `fallback_tool_call_type`, and
`fallback_tool_call_name` when `already_streamed_args` is empty (i.e.,
this is genuinely the first chunk).
- Refactored `_create_remaining_args_delta` to omit header fields
entirely when all fallback values are `None`, which is the correct
behavior for continuing/finishing chunks.

### Does this PR introduce _any_ user-facing change?

Yes. Clients consuming the streaming tool call response will no longer
receive a duplicate `function.name` in the final chunk. This fixes
incorrect behavior visible in the OpenAI-compatible streaming API output
for GLM models using tool calls.

### How was this patch tested?

- Code review and logic analysis of the streaming tool call path in
`patch_glm_tool_call_parser.py`.
- Existing unit tests in
`tests/ut/platform/test_patch_glm_tool_call_parser.py`.

---------

Signed-off-by: chen-weipeng12 <chen-weipeng12@noreply.gitcode.com>
Signed-off-by: chenweiqiang11 <chenweiqiang11@noreply.github.com>
Co-authored-by: chen-weipeng12 <chen-weipeng12@noreply.gitcode.com>

tests/ut/patch/platform/test_patch_glm_tool_call_parser.py

@@ -70,7 +70,11 @@ def test_create_remaining_args_delta_uses_fallback_metadata_for_args_only_delta(
     assert tc.function.arguments == ('{"files":[{"filepath":"HumanEval-X/README.md"}]}')
 
 
-def test_create_remaining_args_delta_prefers_current_metadata_over_fallback():
+def test_create_remaining_args_delta_uses_fallback_over_original_delta():
+    # _create_remaining_args_delta ignores original_delta metadata and uses
+    # the explicit fallback_* parameters instead.  The caller is responsible
+    # for passing non-None fallback values only for the first chunk of a
+    # tool call (when the header has not yet been streamed).
     original_delta = DeltaMessage(
         tool_calls=[
             DeltaToolCall(
@@ -95,9 +99,9 @@ def test_create_remaining_args_delta_prefers_current_metadata_over_fallback():
     )
 
     tc = result.tool_calls[0]
-    assert tc.id == "call_current"
+    assert tc.id == "call_fallback"
     assert tc.type == "function"
-    assert tc.function.name == "current_name"
+    assert tc.function.name == "fallback_name"
     assert tc.function.arguments == "]}"