fix(angular): fix --prod option

fixes #4160

Author: imhoffd

packages/ionic/src/lib/project/angular/build.ts

@@ -58,13 +58,14 @@ ${input('ionic build')} uses the Angular CLI. Use ${input('ng build --help')} to
           summary: `Flag to use the ${input('production')} configuration`,
           type: Boolean,
           hint: weak('[ng]'),
+          groups: ['cordova'],
         },
         ...NG_BUILD_OPTIONS,
         {
           name: 'cordova-assets',
           summary: 'Do not bundle Cordova assets during Cordova build',
           type: Boolean,
-          groups: [MetadataGroup.HIDDEN],
+          groups: [MetadataGroup.HIDDEN, 'cordova'],
           default: true,
         },
       ],