refactor: resolve eslint warnings (max-depth, complexity) - src/lib/validate-processor.ts

[btlghrants]

Describe what should be investigated or refactored

Refactor of src/lib/validate-processor.ts to reduce complexity warnings:

/pepr/src/lib/validate-processor.ts
  15:8  warning  Async function 'validateProcessor' has a complexity of 13. Maximum allowed is 10  complexity
  62:9  warning  Blocks are nested too deeply (4). Maximum allowed is 3                            max-depth

Additional context

Fixes #1381
In support of #1248

[codecov]

Codecov Report

Attention: Patch coverage is 78.26087% with 5 lines in your changes missing coverage. Please review.

Project coverage is 79.82%. Comparing base (35bf589) to head (a539362).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
src/lib/validate-processor.ts	78.26%	4 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1529      +/-   ##
==========================================
+ Coverage   78.97%   79.82%   +0.85%     
==========================================
  Files          40       40              
  Lines        1736     1740       +4     
  Branches      405      413       +8     
==========================================
+ Hits         1371     1389      +18     
+ Misses        335      321      -14     
  Partials       30       30              

Files with missing lines	Coverage Δ
src/lib/validate-processor.ts	54.76% <78.26%> (+41.60%)	⬆️