[sb] use sp to define the status bar battery metrics

Status bar icons scale with font size AND display density, and this
change enables that for the new battery icon.

Also updates the size and arrangement in the shade header to match
status bar.

Test: manual; change font scale and battery size updates
Bug: 402608850
Fixes: 400376762
Fixes: 402059273
Flag: com.android.settingslib.flags.new_status_bar_icons
Flag: com.android.systemui.status_bar_root_modernization
Change-Id: Ifbbdd959f8c6e00bf19348d13c04cdbfdff86abc