chore(skipmaskmanager): remove skip mask files at startup if no frac

[forshev]

Description

Now skip mask manager checks at startup whether existing skipmask file has corresponding fraction. If not, skip mask file is removed

Fixes #426

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[codecov-commenter]

Codecov Report

❌ Patch coverage is 41.17647% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 70.50%. Comparing base (2c48a62) to head (c47fab7).

Files with missing lines	Patch %	Lines
skipmaskmanager/skip_mask_manager.go	41.17%	10 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #427      +/-   ##
==========================================
- Coverage   70.65%   70.50%   -0.15%     
==========================================
  Files         219      219              
  Lines       17009    17021      +12     
==========================================
- Hits        12017    12000      -17     
- Misses       4094     4118      +24     
- Partials      898      903       +5     

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