test: update ng-packagr tests tsconfig as per CLI default

This seems to be the root cause of the failures in the following PR:
angular#17455

Author: alan-agius4

tests/angular_devkit/build_ng_packagr/ng-packaged-ve/tsconfig.json

@@ -6,9 +6,9 @@
     "sourceMap": true,
     "declaration": false,
     "moduleResolution": "node",
-    "emitDecoratorMetadata": true,
     "experimentalDecorators": true,
-    "target": "es5",
+    "target": "es2015",
+    "module": "esnext",
     "typeRoots": [
       "node_modules/@types"
     ],

tests/angular_devkit/build_ng_packagr/ng-packaged/tsconfig.json

@@ -6,9 +6,9 @@
     "sourceMap": true,
     "declaration": false,
     "moduleResolution": "node",
-    "emitDecoratorMetadata": true,
     "experimentalDecorators": true,
-    "target": "es5",
+    "target": "es2015",
+    "module": "esnext",
     "typeRoots": [
       "node_modules/@types"
     ],