Refa: GraphRAG to use async chat methods instead of thread pool execution (#14002)

### What problem does this PR solve?

GraphRAG _async_chat.

### Type of change

- [x] Refactoring
- [x] Performance Improvement


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Refactor**
* Unified chat calls to an async invocation across extractors, improving
timeout handling and ensuring task IDs propagate reliably.
* **Tests**
* Added and expanded unit tests and mocks to cover extractor behavior,
timeout scenarios, and safe test-package imports, reducing regression
risk.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

test/unit_test/test_test_chunk_feedback_package.py

@@ -0,0 +1,21 @@
+import importlib
+import sys
+from types import ModuleType
+
+import pytest
+
+pytestmark = pytest.mark.p2
+
+
+def test_chunk_feedback_package_import_is_safe_when_common_is_shadowed(monkeypatch):
+    shadow_common = ModuleType("common")
+    monkeypatch.setitem(sys.modules, "common", shadow_common)
+    monkeypatch.delitem(
+        sys.modules,
+        "test.testcases.test_web_api.test_chunk_feedback",
+        raising=False,
+    )
+
+    module = importlib.import_module("test.testcases.test_web_api.test_chunk_feedback")
+
+    assert module is not None