Settings: Apply blur only if system theme is selected

Change-Id: I5aafa22fd39c3bd5e570abf69647cb9b1cc1bb1c
Also for onResume

Change-Id: I2c57dac3fa36618e58340eb4820cb6ac4755ee20
fixup custom themes background

Change-Id: Iaf4095a2ecd60244748aa879df82569045b651c2
cleanup derp

Change-Id: I554707856c733304f24b838c433eaa5980338030