(ci) matrix tests for different OS

[ramin]

Refs #1584

Lets run our test suite on multi configurations as they sometimes pass one not other (as reported by @vgonkivs)

• Task: run tests on > 1 OS (previously ubuntu-latest only) now ubuntu-latest and macos-latest
• currently ONLY for the unit tests (do we want to change this for all the tests?)
• also makes a small unrequested tweak to make the execution in go-ci run AFTER the mod and lint checks, so it'll pause if those two fail and fail the entire pipeline faster. Save some wasted compute time, which will be at least x2 worse once we matrix these

example run: https://github.com/celestiaorg/celestia-node/actions/runs/6559066381/job/17813974060

[codecov-commenter]

Codecov Report

Merging #2855 (5e329a3) into main (0b85448) will decrease coverage by 1.12%.
Report is 6 commits behind head on main.
The diff coverage is 87.50%.

@@            Coverage Diff             @@
##             main    #2855      +/-   ##
==========================================
- Coverage   51.16%   50.05%   -1.12%     
==========================================
  Files         167      167              
  Lines       10773    10775       +2     
==========================================
- Hits         5512     5393     -119     
- Misses       4764     4891     +127     
+ Partials      497      491       -6     

Files	Coverage Δ
core/listener.go	53.50% <100.00%> (ø)
nodebuilder/p2p/addrs.go	75.00% <100.00%> (+1.19%)	⬆️
blob/service.go	4.26% <0.00%> (-65.86%)	⬇️

... and 8 files with indirect coverage changes

[Wondertan]

uTack

[Wondertan]

utACK

[distractedm1nd]

utACK