[CSUB-845] Split cleanup of expired entries across multiple blocks

[nathanwhit]

Description of proposed changes

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Practical tips for PR review & merge:

• All GitHub Actions report PASS
• Newly added code/functions have unit tests
  • Coverage tools report all newly added lines as covered
  • The positive scenario is exercised
  • Negative scenarios are exercised, e.g. assert on all possible errors
  • Assert on events triggered if applicable
  • Assert on changes made to storage if applicable
• Modified behavior/functions - try to make sure above test items are covered
• Integration tests are added if applicable/needed

[codecov-commenter]

Codecov Report

Merging #1353 (312ddc5) into dev (283290e) will increase coverage by 0.37%.
The diff coverage is 97.11%.

❗ Current head 312ddc5 differs from pull request most recent head 7180b1e. Consider uploading reports for the commit 7180b1e to get more accurate results

@@            Coverage Diff             @@
##              dev    #1353      +/-   ##
==========================================
+ Coverage   71.07%   71.44%   +0.37%     
==========================================
  Files         107      110       +3     
  Lines       12555    12926     +371     
  Branches      128      128              
==========================================
+ Hits         8923     9235     +312     
- Misses       3622     3681      +59     
  Partials       10       10              

Files	Coverage Δ
pallets/creditcoin/src/mock.rs	100.00% <ø> (ø)
pallets/creditcoin/src/test_utils.rs	100.00% <100.00%> (ø)
pallets/creditcoin/src/tests.rs	98.24% <ø> (ø)
pallets/creditcoin/src/lib.rs	84.97% <97.91%> (+1.78%)	⬆️
pallets/creditcoin/src/types.rs	83.07% <0.00%> (ø)
runtime/src/lib.rs	17.22% <80.00%> (ø)
pallets/creditcoin/src/types/cleanup.rs	92.85% <92.85%> (ø)
pallets/creditcoin/src/tests/cleanup.rs	97.80% <97.80%> (ø)

... and 9 files with indirect coverage changes

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[github-actions]

For full LLVM coverage report click here!

[atodorov]

Overall looks good to me, added a few questions and 1 suggestion

[atodorov]

FTR merging with a few failed CI jobs which aren't critical:

• cargo audit - this is a known failure
• check-version - version string in version.rs was not modified. Normally this will block merge, however these changes are already on main as a hotfix and we want to land them into testnet and bump the version there, before making another release (as part of Release v232 for mainnet #1386). So ignoring this failure for now
• MegaLinter - the 403 response on the white-paper URL I've fixed a while ago, not sure why a rebase didn't resolve that. The rest are spelling errors or issues with files used only during testing, which I think are newly detected by MegaLinter (had to fix one of them in the creditcoin-next repo yesterday). Anyway, none of these are critical and we can address them later.