[XPD] Support Switch style injection

This change implements "style injection" for the switch preference which
uses a MaterialSwitch

...where "style injection" means that the Switch's layouts do not
directly reference any <style>s, but instead receive them via a
corresponding theme <attr>.

Bug: 375480015
Test: manual
Flag: com.android.settingslib.widget.theme.flags.is_expressive_design_enabled
Relnote: N/A
Change-Id: I2ef36a331cc5ba3c4b7112c3e19ea59699228147