`templateUrls` that do not point to actual files are now diagnosed as such
by the Language Service. Support for `styleUrls` will come in a next PR.
This introduces a utility method `getPropertyValueOfType` that scans
TypeScript ASTs until a property assignment whose initializer of a
certain type is found. This PR also notices a couple of things that
could be improved in the language-service implementation, such as
enumerating directive properties and unifying common logic, that will be
fixed in future PRs.
Part of #32564.
PR Close#32586
adeee0fa7f