[dualsim] constrain dual sim RAT height to 12sp

The bug here is that the drawables themselves have weird intrinsic
sizes, and the ones that are narrow sometimes get really big if we use
Modifier.fillMaxHeight.

The fix is to explicitly set their height.

Fixes: 404325538
Test: manual using demo mode
Flag: com.android.settingslib.flags.new_status_bar_icons
Flag: com.android.systemui.status_bar_root_modernization
Change-Id: Iaefff2c9577703757745478ba6dbe27127d05363