Set traceName automatically for Hydrator

The traceName will automatically be passed as the property name when by
is used. Old `hydratedStateOf` methods are kept to support non-by usage
and explicit traceName.

Usage: `val myState by hydratedStateOf()``

Bug: b/420591935
Test: Refactor only
Flag: com.android.systemui.scene_container
Change-Id: Ibea95a6d37a29c2cd32600d8d87eade105d8b6e9