Commit a0b2d36#diff-3975e0ee5aa3e06ecbcd76f5fa5134612f7fd2e6802ca7d370973bd410aab55cR25-R31 changed the serialization phase logic so
that when the state is empty the script tag is not added to the document. As a side effect, this caused the `toJson` not called which caused the `onSerialize` callbacks also not to be called.
These callbacks are used to provide the value for a key when `toJson` is called. Example: ngrx/platform#101 (comment)

Closes #47172

PR Close #47888

Before
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Now
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PR Close #47891

… shorter and clearer. (#47897)

PR Close #47897

…h shadow DOM (#47903)

`AnimationRendererFactory` maintains a map between a renderer delegate and the animations renderer it corresponds to, but the renderers are never removed from the map. This leads to memory leaks when used with the `ShadowDom` view encapsulation, because the specific renderer keeps a references to its shadow root which in turn references all the elements in the view.

These changes resolve the leak by clearing the reference when the animations renderer is destroyed.

Fixes #47892.

PR Close #47903

PR Close #47910