refactor(docs-infra): update docs examples tslint.json to match CLI and fix failures (#38143)

This commit updates the `tslint.json` configuration file, that is used
to lint the docs examples, to match the one generated for new Angular
CLI apps. There are some minimal differences (marked with `TODO`
comments) for things, such as component selector prefix, that would
require extensive and/or difficult to validate changes in guides.

This commit also includes the final adjustments to make the docs
examples code compatible with the new tslint rules. (The bulk of the
work has been done in previous commits.)

PR Close #38143

aio/content/examples/testing/src/app/dashboard/dashboard.component.spec.ts

@@ -90,7 +90,7 @@ function compileAndCreate() {
  * The (almost) same tests for both.
  * Only change: the way that the first hero is clicked
  */
-function tests(heroClick: Function) {
+function tests(heroClick: () => void) {
 
   it('should NOT have heroes before ngOnInit', () => {
     expect(comp.heroes.length).toBe(0,