fix(tests): skip bash tool tests on Windows

Merge #5680

## Summary

This fixes Windows test collection for `tests/unittests/tools/test_bash_tool.py`.

The test module imports Python's `resource` module at import time, but `resource` is Unix-only and unavailable on Windows. As a result, running the targeted test on Windows fails during collection before pytest can report a skip.

This change adds a module-level Windows skip before importing `resource`.

## Validation

Ran on Windows 10 with Python 3.12:

- `python -m pytest tests/unittests/tools/test_bash_tool.py -q`
- `python -m pytest tests/unittests/platform -q`
- `python -m pytest tests/unittests/utils/test_env_utils.py -q`

Co-authored-by: George Weale <gweale@google.com>
PiperOrigin-RevId: 930811714

Author: GWeale

tests/unittests/tools/test_bash_tool.py

@@ -13,14 +13,22 @@
 # limitations under the License.
 
 import asyncio
-import resource
 import signal
+import sys
 from unittest import mock
 
+import pytest
+
+if sys.platform == "win32":
+  pytest.skip(
+      "bash tool tests require Unix resource module", allow_module_level=True
+  )
+
+import resource
+
 from google.adk.tools import bash_tool
 from google.adk.tools import tool_context
 from google.adk.tools.tool_confirmation import ToolConfirmation
-import pytest
 
 
 @pytest.fixture