feat: cleanup VaultStartBlockNumbers upon epoch expiry

[nmammeri]

Pull Request

Closes: PRO-1699

Checklist

Please conduct a thorough self-review before opening the PR.

• [x] I am confident that the code works.
• [x] I have written sufficient tests.
• [x] I have written and tested required migrations.
• [x] I have updated documentation where appropriate.

Summary

• Implemented cleaning VaultStartBlockNumbers upon epoch expiry
• It's implemented in a simple way where it removes all epochs <= expired_epoch. This means that it would be expensive the first time we run this.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 71%. Comparing base (c5f26eb) to head (52cc688). Report is 8 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #5450 +/- ## ====================================== - Coverage 72% 71% -1% ====================================== Files 491 494 +3 Lines 86776 87573 +797 Branches 86776 87573 +797 ====================================== + Hits 62477 62526 +49 - Misses 21699 22436 +737 - Partials 2600 2611 +11 ```

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