This commit adds a new integration test which will help ensure that all
exported `@NgModule`'s of framework packages can be imported by users
without any errors.
This test is generally useful, but with our upcoming changes with
relative imports, this is a good safety-net. Relative imports could
break re-exported NgModules inside NgModule's. For more details, see:
https://github.com/angular/components/pull/30667
Notably we don't expect any issues for framework package as re-exporting
`@NgModule`'s inside `@NgModule`'s is seemingly a rather rare pattern for
APF libraries (confirmed by Material only having like 4-5 instances).
PR Close#60489
