refactor(material/core): deprecate initialized mixin

[crisbeto]

The mixinInitialized is only used in a couple of places and it takes more boilerplate code to consume than to recreate its functionality. It also basically recreates the implementation of ReplaySubject.

These changes deprecate the mixin and remove its usages from our code so that we can eventually drop it in version 17.

[crisbeto]

Note: I ran an initial TGP for this and it broke a bunch of targets. It likely introduced a behavior change somewhere.

[crisbeto]

Closing since I'm approaching removing the mixin functions differently.

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