Add systemGestureExclude rect to brightness slider

This change creates a generic modifier that can be used to exclude
left/right swipe from the edges of the device for components in the
QuickSettingsShade by adding the corresponding padding.

Also, makes sure that brightness has the correct height (include the
border as part of the internal padding.

Test: manual, legacy and dual shade
Flag: com.android.systemui.qs_ui_refactor_compose_fragment
Flag: com.android.systemui.scene_container
Fixes: 395701064
Change-Id: Ib9505ac95399823bde16b6c8223543fec823c5b1