RELOPS-2213: Add win11 ARM64 25H2 OS integration worker-pool support

[jwmossmoz]

Summary

• add missing OS integration workflow options for win11-a64-25h2-tester-alpha and win11-a64-25h2-builder-alpha
• extend integration-test pool variant matching to include win11 ARM64 tester and builder families
• add a unit test that verifies a requested 25H2 ARM64 tester image maps to win11-a64-25h2-tester-alpha

Jira

• RELOPS-2213

Related

• Follow-up to RELOPS-2212
• RELOPS-2212 PR: RELOPS-2212: Select image-compatible OS integration alpha pools #720

Validation

• uv run --with ruff ruff check taskcluster/worker_images_taskgraph/transforms/integration_test.py taskcluster/test/test_integration_test_transform.py
• PYTHONPATH=taskcluster uv run --with ty ty check taskcluster/worker_images_taskgraph/transforms/integration_test.py taskcluster/test/test_integration_test_transform.py
• PYTHONPATH=taskcluster uv run python -m unittest discover -s taskcluster/test -p 'test_integration_test_transform.py'