Revert "fix: expire all previous epochs (#5279)"

[kylezs]

Pull Request

Checklist

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

Summary

Reason this was causing issues is still be investigated. But CI has passed twice without this commit and has been failing on everything when this commit was included.

[codecov]

Codecov Report

Attention: Patch coverage is 78.04878% with 18 lines in your changes missing coverage. Please review.

Project coverage is 71%. Comparing base (5baa3dd) to head (7ff7794).

Files with missing lines	Patch %	Lines
state-chain/custom-rpc/src/lib.rs	0%	11 Missing ⚠️
state-chain/runtime/src/lib.rs	0%	1 Missing and 3 partials ⚠️
state-chain/pallets/cf-validator/src/lib.rs	75%	3 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff           @@
##            main   #5362    +/-   ##
======================================
- Coverage     71%     71%    -0%     
======================================
  Files        496     495     -1     
  Lines      86485   86298   -187     
  Branches   86485   86298   -187     
======================================
- Hits       61751   61515   -236     
- Misses     21971   22020    +49     
  Partials    2763    2763            

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