feat(anta): Added test case to verify Spanning Tree (RPVST) state(stable topology)

[vitthalmagadum]

Description

Verifies the number of changes across all interfaces in the Spanning Tree Protocol (STP) topology is below a threshold.

Expected Results
----------------
* Success: The test will pass if the total number of changes across all interfaces is less than the specified threshold.
* Failure: The test will fail if the total number of changes across all interfaces meets or exceeds the specified threshold,
indicating potential instability in the topology.

Fixes #782

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)

[MaheshGSLAB]

LGTM

[carl-baillargeon]

Can you add unit tests with outputs from different configured spanning-tree modes (mstp, rapid-pvst, rstp, none)?

DC1-LEAF1A(config)#spanning-tree mode ?
  backup      Backup port mode
  mstp        Multiple spanning tree protocol
  none        Disable spanning tree
  rapid-pvst  Per VLAN rapid spanning tree protocol
  rstp        Rapid spanning tree protocol

[github-actions]

This pull request has conflicts, please resolve those before we can evaluate the pull request.

[github-actions]

Conflicts have been resolved. A maintainer will review the pull request shortly.

[vitthalmagadum]

Can you add unit tests with outputs from different configured spanning-tree modes (mstp, rapid-pvst, rstp, none)?

DC1-LEAF1A(config)#spanning-tree mode ?
  backup      Backup port mode
  mstp        Multiple spanning tree protocol
  none        Disable spanning tree
  rapid-pvst  Per VLAN rapid spanning tree protocol
  rstp        Rapid spanning tree protocol

Added unit test for rstp mode.

[sonarcloud]

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 SonarCloud

[carl-baillargeon]

LGTM