AngularFireAuth.authState incorrectly uses onIdTokenChanged

[sarunint]

Version info

Angular: 8.2.14

Firebase: 7.8.0

AngularFire: 5.4.0

How to reproduce these conditions

In #2294, AngularFireAuth.authState had been incorrectly refactored to used auth.onIdTokenChanged. It should be auth.onAuthStateChanged

angularfire/src/auth/auth.ts

Lines 50 to 52 in 0ae30d8

	this.authState = new Observable<User | null>(subscriber => {
	return zone.runOutsideAngular(() => this.auth.onIdTokenChanged(subscriber));
	}).pipe(keepUnstableUntilFirst);;

This only applies to v5 branch, does not effect master branch.

[jamesdaniels]

Addressed in 5.4.1, thanks for the PR!