refactor(@angular/cli): remove unused `NgToolkitError`
refactor(@angular/cli): remove unused `NgToolkitError`

geofffilippi/angular-cli,geofffilippi/angular-cli,clydin/angular-cli,angular/angular-cli,Brocco/angular-cli,Brocco/angular-cli,catull/angular-cli,geofffilippi/angular-cli,geofffilippi/angular-cli,Brocco/angular-cli,clydin/angular-cli,angular/angular-cli,angular/angular-cli,angular/angular-cli,clydin/angular-cli,catull/angular-cli,catull/angular-cli,catull/angular-cli,clydin/angular-cli,Brocco/angular-cli,Brocco/angular-cli