Recreate taskbar when dark mode changes

Also dispatch sysui flags to all controllers upon recreate, not just NavbarButtonsViewController. Additionally, tell the controllers to skip the animation due to the flag changes if it's fromInit.

Test: Enable themed icons, switch dark theme in quick settings, ensure taskbar updates
Fixes: 204403933
Change-Id: Ic43a50cf0456175f9beba5c29360440f051cbd2d