[Flexiglass] Use TileGrid to replace the legacy QS view

This CL replaces the legacy QS view with TileGrid. This CL also adjusts
the paddings of the brightness bar.

Bug: 420960164
Flag: com.android.systemui.scene_container
Test: com.android.systemui.qs.ui.composable.QuickSettingsSceneTest
Change-Id: Ice3b95e4ed9229cfa7b55e8e858e6efdc4a88e3c