Hide haptic intensity settings for devices without enough dynamic range.

Despite our hope, devices prior to P18 just don't have the dynamic range
to give three distinct vibration intensity settings. Given this, only
show an on / off toggle for devices by default unless they explicitly
opt-in to multiple intensity levels.

Test: m -j RunSettingsRoboTests
Bug: 80243632
Change-Id: I14ece855cf20f9fa44b0648d28f89c0053be5c5f