chore: fix liveSync of html files in Angular apps

[rosen-vladimirov]

In case you change .html file in Angular application, during tns run <platform> --bundle, the application will be restarted and an error will be shown.
This happens as in some cases, the getCompiledFile method from Angular compiler does not throw an error when it is unable to find a file, but instead it returns an object with empty outputText and array of errors (errorDependencies).
Fix the liveSync in these cases by checking the result of the Angular compiler and fallback to non-platform specific file in the mentioned case.

PR Checklist

• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/CONTRIBUTING.md#commit-messages.
• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
• You have signed the CLA.
• All existing tests are passing: https://github.com/NativeScript/nativescript-dev-webpack/blob/master/CONTRIBUTING.md#testing-locally-by-running-e2e-tests
• Tests for the changes are included.

What is the current behavior?

Unable to use LiveSync in Angular applications.

What is the new behavior?

LiveSync works in Angular applications.

Fixes/Implements/Closes #[Issue Number].