test(docs-infra): use existing `MockLogger` class in `SwUpdatesService` tests (#39651)
test(docs-infra): use existing `MockLogger` class in `SwUpdatesService` tests (#39651)

Since we have a `MockLogger` class in `src/testing/`, there is no need
to create a new `MockLogger` class for the `SwUpdatesService` unit
tests.

This commit switches to using the `MockLogger` class from
`src/testing/`.

PR Close #39651

ocombe/angular,blesh/angular,gkalpak/angular,alxhub/angular,angular/angular,IdeaBlade/angular,JiaLiPassion/angular,ocombe/angular,gnomeontherun/angular,manekinekko/angular,JiaLiPassion/angular,brandonroberts/angular,angular-indonesia/angular,angular-indonesia/angular,brandonroberts/angular,JiaLiPassion/angular,IdeaBlade/angular,brandonroberts/angular,brandonroberts/angular,blesh/angular,angular-indonesia/angular,blesh/angular,blesh/angular,manekinekko/angular,angular/angular,mgechev/angular,manekinekko/angular,gnomeontherun/angular,alxhub/angular,shairez/angular,gnomeontherun/angular,brandonroberts/angular,angular-indonesia/angular,alxhub/angular,manekinekko/angular,ocombe/angular,angular/angular,mgechev/angular,shairez/angular,JiaLiPassion/angular,gkalpak/angular,ocombe/angular,manekinekko/angular,IdeaBlade/angular,brandonroberts/angular,mgechev/angular,mgechev/angular,IdeaBlade/angular,blesh/angular,alxhub/angular,shairez/angular,angular/angular,gkalpak/angular,gkalpak/angular,shairez/angular,ocombe/angular,gnomeontherun/angular,ocombe/angular,mgechev/angular,shairez/angular,manekinekko/angular,IdeaBlade/angular,alxhub/angular