Add validation for tsconfig in ng subfolder

[mhenkens]

I'm submitting a...

[ ] Regression (a behavior that used to work and stopped working in a new release)
[ ] Bug report  
[X] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead see https://github.com/NationalBankBelgium/stark/blob/master/CONTRIBUTING.md#got-a-question-or-problem

Current behavior

In current build process, the validations are performed for tsconfig files but only in mains folders and the validation for angular specific tsconfig are missing

Minimal reproduction of the problem with instructions

What is the motivation / use case for changing the behavior?

We experiencing a miss configuration in one of the angular tsconfig. that lead to create the issue #539. To avoid same issue in the future.

Environment

Angular CLI: 13
Node: 20
Angular: 13

For Tooling issues:
- Node version: v20.0.0  
- Platform:  All

Others: