ci: update IssueLens triage action for stream timeout fix

[Changyong Gong (chagong)]

Summary

Update the IssueLens issue-loop action in .github/workflows/issuelens-run.yml to the timeout-fixed revision a81d2d96167fc0e69ac631c2edc85f858e693289 from microsoft/IssueLens#53.

The fix increases client stream inactivity tolerance from 60 seconds to 300 seconds, while retaining the 15-minute total read budget. This prevents valid pauses between events from prematurely disconnecting and cancelling the hosted triage agent. No redeployment is needed.

This is a single-line action-pin update. Team-memory workflow pins, other actions, triggers, permissions, secrets, and repository policy are unchanged.

Validation

• Parsed all five GitHub Actions workflow YAML files using existing PyYAML 6.0.3.
• Verified the old revision is an ancestor of the target revision, so this is an upgrade rather than a downgrade.
• Asserted the exact one-line replacement, unchanged workflow structure, and complete coverage of the repository's IssueLens issue-loop action references.
• git diff --check passed; no live triage or deployment was invoked.

[wenyt (wenytang-ms)]

Reviewed the exact one-line IssueLens action pin update and cross-checked the eight related PRs. This issue-loop workflow is byte-for-byte identical to the other six equivalent callers. Triggers, permissions, inputs, and team-memory workflow pins are unchanged. Checked target action compatibility and cumulative upstream action changes; the shared stream timeout is 300 seconds and the total read budget remains 900 seconds. No blocking issues found in this change.