Parallelizing contrib check

[TylerHelmuth]

Description:
Implements a job matrix for the contrib checks. If we think it would be worth it, we could add a setup job to download the repo only 1 time.

Link to tracking Issue:

Related to open-telemetry/opentelemetry-collector-contrib#30880

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (89388ad) 90.24% compared to head (f7b6685) 90.25%.
Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9449      +/-   ##
==========================================
+ Coverage   90.24%   90.25%   +0.01%     
==========================================
  Files         344      344              
  Lines       17932    17932              
==========================================
+ Hits        16182    16185       +3     
+ Misses       1421     1419       -2     
+ Partials      329      328       -1     

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