fix(@angular/cli): add missing experimentalRollupPassin CLI schema

Author: alan-agius4

packages/angular/cli/lib/config/schema.json

@@ -950,6 +950,11 @@
                 "use-credentials"
               ]
             },
+            "experimentalRollupPass": {
+              "type": "boolean",
+              "description": "Concatenate modules with Rollup before bundling them with Webpack.",
+              "default": false
+            },
             "allowedCommonJsDependencies": {
               "description": "A list of CommonJS packages that are allowed to be used without a build time warning.",
               "type": "array",