[python] Add ARM operation-templates nextLink paging coverage for mock API tests

[Copilot]

This updates the Python mock API suite to cover the ARM operation-templates paging scenario introduced in Azure/typespec-azure#5214. The tests now validate that post_action_paging consumes the nextLink page, not just the first page.

• Spec version alignment

  • Bumped @azure-tools/azure-http-specs in packages/http-client-python to 0.1.0-alpha.45-dev.3 so the new paging contract (@nextLink on MonitoredResourceListResponse.nextLink) is available to the test pipeline.

• Mock API paging assertions (sync + async)

  • Extended:
    • tests/mock_api/azure/test_azure_arm_operationtemplates.py
    • tests/mock_api/azure/asynctests/test_azure_arm_operationtemplates_async.py
  • test_paging_post_action_paging now asserts two items are returned and validates second-page content (vm2, sending_metrics=False), confirming continuation traversal.

• Changelog

  • Added an internal Chronus entry for @typespec/http-client-python describing the new nextLink paging coverage.

items = list(result)
assert len(items) == 2
assert items[0].id.endswith("/vm1")
assert items[1].id.endswith("/vm2")
assert items[1].sending_metrics is False

• Fixes [python] add test case for https://github.com/Azure/typespec-azure/pull/5214 #11723

[azure-pipelines]

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