[battery] don't round the fill rect

The clip / rounded rects widths were swapped.

Test: visual
Bug: 400783306
Flag: com.android.settingslib.flags.new_status_bar_icons
Flag: com.android.systemui.status_bar_root_modernization
Change-Id: I8dc48c72cb0bb9505948e030c20fae8dd288db81