feat(anta): Added the test case to verify the Graceful Restart (GR) and GR-Helper

[geetanjalimanegslab]

Description

This test performs the following checks:
1. Verifies that the ISIS is configured.
3. Verifies that the specified ISIS instance is found.
4. Verifies that the IS-IS graceful restart and graceful helper are set as expected in the inputs.

Expected Results

• Success: The test will pass if all of the following conditions are met:
  • The ISIS is configured on the device.
  • The specified ISIS instance is found
  • The expected and actual IS-IS graceful restart and graceful helper values are matched.
• Failure: The test will fail if any of the following conditions is met:
  • The ISIS is not configured on the device.
  • The specified ISIS instance is not found.
  • The Expected and actual IS-IS graceful restart and graceful helper values are not matched.

Fixes #882

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have run pre-commit for code linting and typing (pre-commit run)
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes (tox -e testenv)

[codspeed-hq]

CodSpeed Performance Report

Merging #988 will not alter performance

_{Comparing geetanjalimanegslab:test_isis_graceful_restart (44ed38a) with main (1f033f4)}

Summary

✅ 22 untouched benchmarks

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[carl-baillargeon]

Blocking this until #963 is merged.