Fix:Stop the rotation of validatorSet at any update in it.

[VAIBHAVJINDAL3012]

Description

In the current system, at every update in validatorSet, we rotate it and change the proposer. With the frequent updates, proposer also changes frequently.
This PR include the change which has stopped the rotation of validatorSet in endBlocker after any update in the validatorSet.
Implementation of this change require the Hardfork.

Please provide a detailed description of what was done in this PR

Changes

• Bugfix (non-breaking change that solves an issue)
• [✓] Hotfix (change that solves an urgent issue, and requires immediate attention)
• New feature (non-breaking change that adds functionality)
• [✓] Breaking change (change that is not backwards-compatible and/or changes current functionality)
• Changes only for a subset of nodes

Breaking changes

This change require the Hardfork.

Nodes audience

It needs to deployed on all the validator nodes.

Checklist

• [ ✓] I have added at least 2 reviewer or the whole pos-v1 team
• [✓] I have added sufficient documentation in code
• [✓] I will be resolving comments - if any - by pushing each fix in a separate commit and linking the commit hash in the comment reply

Cross repository changes

• This PR requires changes to bor
  • In case link the PR here:
• This PR requires changes to matic-cli
  • In case link the PR here:

Testing

• I have added unit tests
• I have added tests to CI
• [✓] I have tested this code manually on local environment
• [✓] I have tested this code manually on remote devnet using express-cli
• I have tested this code manually on mumbai
• I have created new e2e tests into express-cli

[codecov]

Codecov Report

Patch coverage has no change and project coverage change: -0.02% ⚠️

Comparison is base (c7ec9d5) 75.40% compared to head (fc117bf) 75.38%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #983      +/-   ##
===========================================
- Coverage    75.40%   75.38%   -0.02%     
===========================================
  Files           49       49              
  Lines         5309     5310       +1     
===========================================
  Hits          4003     4003              
- Misses        1071     1072       +1     
  Partials       235      235              

Files Changed	Coverage Δ
app/app.go	82.64% <0.00%> (-0.18%)	⬇️

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[github-actions]

This PR is stale because it has been open 21 days with no activity. Remove stale label or comment or this will be closed in 14 days.

[github-actions]

This PR was closed because it has been stalled for 35 days with no activity.

[github-actions]

This PR is stale because it has been open 21 days with no activity. Remove stale label or comment or this will be closed in 14 days.

[github-actions]

This PR is stale because it has been open 21 days with no activity. Remove stale label or comment or this will be closed in 14 days.

[github-actions]

This PR is stale because it has been open 21 days with no activity. Remove stale label or comment or this will be closed in 14 days.