refactor: remove change is tsconfig app

Author: anandtiwary

tsconfig.app.json

@@ -2,8 +2,7 @@
   "extends": "./tsconfig.json",
   "compilerOptions": {
     "outDir": "./out-tsc/app",
-    "types": [],
-    "strictNullChecks": true
+    "types": []
   },
   "files": ["src/main.ts", "src/polyfills.ts"],
   "include": ["src/**/*.ts"],