This commit removes a number of obsolete integration tests and also removes some e2e tests for a few remianing apps, since they are not adding value, but cause extra time to spend on CI.
PR Close#60594
Adds support for TypeScript 4.8 and resolves some issues that came up as a result of the update.
Most of the issues came from some changes in TypeScript where the `decorators` and `modifiers` properties were removed from most node types, and were combined into a single `modifiers` array. Since we need to continue supporting TS 4.6 and 4.7 until v15, I ended up creating a new `ngtsc/ts_compatibility` directory to make it easier to reuse the new backwards-compatible code.
PR Close#47038
Jessica Janiuk