ci: saucelabs-legacy job should not run schematic core tests (#29124)
ci: saucelabs-legacy job should not run schematic core tests (#29124)

With 62157990554306fb76e1e254b31855f966ff65f2 we introduced schematics
for `core`, but due to the fact the Saucelabs legacy job does not run
for PRs, we didn't realize that the legacy Saucelabs job ends up
running the schematic specs.

We don't want to run these schematic tests in the legacy-saucelabs job,
as these are node-only specs and the non-Bazel Karma setup is not set
up to provide the devkit schematic node modules.

We exclude the schematics folder in the `core` package in the
legacy-build tsconfig file (similar to how it is done for elements)

PR Close #29124

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