ci: only lint commit messages on PRs (#35035)
ci: only lint commit messages on PRs (#35035)

As all commit messages are linted during the PR process, we
do not need to relint these previous commit messages on upstream
branches.

PR Close #35035

snaptech/angular,IdeaBlade/angular,blesh/angular,angular-indonesia/angular,shairez/angular,gnomeontherun/angular,gnomeontherun/angular,Toxicable/angular,Toxicable/angular,manekinekko/angular,StephenFluin/angular,filipesilva/angular,gdi2290/angular,mgechev/angular,IdeaBlade/angular,manekinekko/angular,alxhub/angular,angular-indonesia/angular,JiaLiPassion/angular,gdi2290/angular,blesh/angular,brandonroberts/angular,shairez/angular,snaptech/angular,ocombe/angular,gdi2290/angular,JiaLiPassion/angular,wKoza/angular,matsko/angular,JiaLiPassion/angular,ocombe/angular,StephenFluin/angular,snaptech/angular,snaptech/angular,snaptech/angular,filipesilva/angular,StephenFluin/angular,blesh/angular,ocombe/angular,blesh/angular,mgechev/angular,gkalpak/angular,alxhub/angular,Toxicable/angular,filipesilva/angular,gdi2290/angular,wKoza/angular,StephenFluin/angular,blesh/angular,gkalpak/angular,StephenFluin/angular,snaptech/angular,gnomeontherun/angular,angular/angular,wKoza/angular,shairez/angular,wKoza/angular,IdeaBlade/angular,angular-indonesia/angular,shairez/angular,mgechev/angular,filipesilva/angular,gkalpak/angular,IdeaBlade/angular,gdi2290/angular,manekinekko/angular,alxhub/angular,gnomeontherun/angular,wKoza/angular,angular/angular,brandonroberts/angular,mgechev/angular,filipesilva/angular,shairez/angular,matsko/angular,angular/angular,brandonroberts/angular,manekinekko/angular,gdi2290/angular,mgechev/angular,JiaLiPassion/angular,matsko/angular,manekinekko/angular,ocombe/angular,alxhub/angular,angular/angular,ocombe/angular,gkalpak/angular,IdeaBlade/angular,matsko/angular,Toxicable/angular,brandonroberts/angular,angular-indonesia/angular,Toxicable/angular,manekinekko/angular,Toxicable/angular,wKoza/angular,brandonroberts/angular,matsko/angular,brandonroberts/angular,alxhub/angular,ocombe/angular