fix(docs-infra): re-enable SW offline mode (#25826)
fix(docs-infra): re-enable SW offline mode (#25826)

This basically reverts #25692, since Firebase has fixed the issue with
`/index.html` redirection on their side.

PR Close #25826

brandonroberts/angular,manekinekko/angular,StephenFluin/angular,vikerman/angular,hansl/angular,mlaval/angular,mgechev/angular,gkalpak/angular,JiaLiPassion/angular,blesh/angular,wKoza/angular,Brocco/angular,ultrasonicsoft/angular,ValtoFrameworks/Angular-2,StephenFluin/angular,matsko/angular,brandonroberts/angular,alexeagle/angular,mprobst/angular,ocombe/angular,ValtoFrameworks/Angular-2,IdeaBlade/angular,wKoza/angular,kegluneq/angular,matsko/angular,Toxicable/angular,gdi2290/angular,Brocco/angular,ocombe/angular,hansl/angular,shairez/angular,blesh/angular,gdi2290/angular,IdeaBlade/angular,ultrasonicsoft/angular,petebacondarwin/angular,juristr/angular,StephenFluin/angular,kegluneq/angular,JiaLiPassion/angular,angular-indonesia/angular,sarunint/angular,jasonaden/angular,brandonroberts/angular,wKoza/angular,ultrasonicsoft/angular,gkalpak/angular,angular/angular,shairez/angular,sarunint/angular,filipesilva/angular,hansl/angular,mlaval/angular,IgorMinar/angular,ValtoFrameworks/Angular-2,Toxicable/angular,shairez/angular,kegluneq/angular,snaptech/angular,brandonroberts/angular,Brocco/angular,sarunint/angular,kara/angular,brandonroberts/angular,sarunint/angular,mgechev/angular,StephenFluin/angular,alexeagle/angular,StephenFluin/angular,juristr/angular,snaptech/angular,juristr/angular,angular/angular,mhevery/angular,trshafer/angular,petebacondarwin/angular,kegluneq/angular,petebacondarwin/angular,trshafer/angular,vikerman/angular,IgorMinar/angular,sarunint/angular,trshafer/angular,mlaval/angular,mlaval/angular,IdeaBlade/angular,JiaLiPassion/angular,alexeagle/angular,snaptech/angular,shairez/angular,blesh/angular,alexeagle/angular,ultrasonicsoft/angular,gnomeontherun/angular,wKoza/angular,wKoza/angular,kegluneq/angular,alxhub/angular,alxhub/angular,gdi2290/angular,mgechev/angular,Toxicable/angular,blesh/angular,alxhub/angular,IgorMinar/angular,Brocco/angular,angular-indonesia/angular,alexeagle/angular,matsko/angular,petebacondarwin/angular,vikerman/angular,gkalpak/angular,manekinekko/angular,ocombe/angular,mgechev/angular,manekinekko/angular,alxhub/angular,IdeaBlade/angular,vikerman/angular,angular-indonesia/angular,vikerman/angular,gnomeontherun/angular,angular-indonesia/angular,IgorMinar/angular,petebacondarwin/angular,IgorMinar/angular,snaptech/angular,mprobst/angular,Toxicable/angular,hansl/angular,mlaval/angular,filipesilva/angular,filipesilva/angular,trshafer/angular,gnomeontherun/angular,jasonaden/angular,manekinekko/angular,jasonaden/angular,ocombe/angular,kara/angular,mhevery/angular,JiaLiPassion/angular,gdi2290/angular,ValtoFrameworks/Angular-2,ultrasonicsoft/angular,filipesilva/angular,IgorMinar/angular,gdi2290/angular,mprobst/angular,ValtoFrameworks/Angular-2,snaptech/angular,jasonaden/angular,manekinekko/angular,shairez/angular,mprobst/angular,trshafer/angular,kegluneq/angular,kara/angular,Brocco/angular,matsko/angular,mhevery/angular,gnomeontherun/angular,jasonaden/angular,angular/angular,petebacondarwin/angular,mhevery/angular,jasonaden/angular,sarunint/angular,kara/angular,angular/angular,mprobst/angular,alxhub/angular,juristr/angular,juristr/angular,wKoza/angular,kara/angular,alexeagle/angular,Toxicable/angular,Toxicable/angular,mgechev/angular,Brocco/angular,trshafer/angular,manekinekko/angular,mhevery/angular,ocombe/angular,ultrasonicsoft/angular,brandonroberts/angular,hansl/angular,IdeaBlade/angular,juristr/angular,ocombe/angular,filipesilva/angular,matsko/angular,kara/angular,mprobst/angular,gdi2290/angular,blesh/angular,hansl/angular,gkalpak/angular,snaptech/angular,mhevery/angular,vikerman/angular