Don't do a full frontend release build in test-frontend job, added typescheck…

Don't do a full frontend release build in test-frontend job, added typescheck (tsc noEmit) instead, fixes #14639

scripts/circle-test-frontend.sh

@@ -11,4 +11,3 @@ function exit_if_fail {
 }
 
 exit_if_fail npm run test
-exit_if_fail npm run build

scripts/grunt/default_task.js

@@ -10,8 +10,9 @@ module.exports = function (grunt) {
 
   grunt.registerTask('test', [
     'sasslint',
+    'exec:tsc',
     'exec:tslint',
-    "exec:jest",
+    'exec:jest',
     'no-only-tests'
   ]);