Add parsing of "isHomeSupported" in DisplayWindowSettingsProvider

Introduce support for reading the "isHomeSupported" boolean attribute from XML configuration files in DisplayWindowSettingsProvider.

The new implementation:
1.Adds mIsHomeSupported field initialization using getBooleanAttribute.
2.Uses null as default value to maintain existing behavior when attribute is missing.
3.Follows established pattern for attribute parsing in the class

BUG:417321221
Flag: EXEMPT bugfix
(cherry picked from https://partner-android-review.googlesource.com/q/commit:ce4f437592cf6a3c59bd77e329284327217a772c)
Merged-In: I7b86869907c09e496d4f15dea6ab3c92c53276b1
Change-Id: I7b86869907c09e496d4f15dea6ab3c92c53276b1