Chore: explicitly reset vault rotator state on ceremony restarts

[msgmaxim]

Pull Request

Checklist

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

• I am confident that the code works.
• I have updated documentation where appropriate.

Summary

Currently when we restart from keygen or handover (as opposed to "aborting"), vault rotator states don't get fully reset. I don't think it is actually a problem since we always overwrite values before starting to use them, but as discussed with Dan, it is better to reset them explicitly the moment they become stale.

I renamed abort_vault_rotation to reset_vault_rotation since it we now use it in situations other than aborts, and removed the VaultRotationAborted to avoid extra noise (it was only added recently and seems redundant considering that we already have RotationAborted in the validator pallet).

[codecov]

Codecov Report

Merging #3907 (2d96fdf) into main (7911f33) will decrease coverage by 0%.
The diff coverage is 100%.

@@          Coverage Diff          @@
##            main   #3907   +/-   ##
=====================================
- Coverage     71%     71%   -0%     
=====================================
  Files        366     366           
  Lines      56762   56772   +10     
  Branches   56762   56772   +10     
=====================================
- Hits       40540   40533    -7     
- Misses     14213   14222    +9     
- Partials    2009    2017    +8     

Files Changed	Coverage Δ
state-chain/traits/src/lib.rs	52% <ø> (ø)
state-chain/pallets/cf-validator/src/lib.rs	74% <100%> (+<1%)	⬆️
state-chain/pallets/cf-vaults/src/tests.rs	97% <100%> (ø)
state-chain/pallets/cf-vaults/src/vault_rotator.rs	73% <100%> (-<1%)	⬇️
...-chain/runtime/src/chainflip/all_vaults_rotator.rs	97% <100%> (ø)
state-chain/traits/src/mocks/vault_rotator.rs	94% <100%> (ø)

... and 2 files with indirect coverage changes

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[syan095]

LGTM