fix(aio): tsconfig.app.json excludes all testing files (#20779)

Fixes app build error in testing guide which has testing folder at multiple levels,
with files in them referring to files in the root `testing` folder.
Also removed the exclusion of files with `.1` in the name because
all app `.ts` files must be buildable per aio policy.
must build

PR Close #20779

aio/tools/examples/shared/boilerplate/cli/src/tsconfig.app.json

@@ -9,7 +9,6 @@
   "exclude": [
     "test.ts",
     "**/*.spec.ts",
-    "testing/**",
+    "**/testing/*"
-    "**/*.1.*"
   ]
 }