Always run warningsAsErrors on CI

[BraisGabin]

Merging #3724 I introduced a regresion disabled what I enabled at #3646

Anywy I found that my previous approuch wasn't good enought because warningsAsErrors mess up with the gradle cache so we want to have a consistent value for warningsAsErrors in all out CI. For this reason I change this in the gradle files instead of adding the flag in the workflows.

(I'm adding a stub commit to ensure that this do what it's meant to do) Done, and it works like a charm.

[codecov]

Codecov Report

Merging #3754 (24c87ae) into main (7cc0c9d) will increase coverage by 0.02%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##               main    #3754      +/-   ##
============================================
+ Coverage     78.73%   78.75%   +0.02%     
- Complexity     2896     2900       +4     
============================================
  Files           473      473              
  Lines          9335     9336       +1     
  Branches       1721     1722       +1     
============================================
+ Hits           7350     7353       +3     
  Misses         1075     1075              
+ Partials        910      908       -2     

Impacted Files	Coverage Δ	Complexity Δ
.../rules/documentation/UndocumentedPublicProperty.kt	88.46% <0.00%> (+8.46%)	28.00% <0.00%> (+4.00%)

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