Handle return value when Bluetooth is enabled

If the Bluetooth enable(true) returns false currently we are waiting for
a broadcast (which may not happen if enable returns false). We mark the
toggle to have failed (i.e. it is clickable and in OFF state) and the
switch bar text is appropriately shown.

Bug: b/28318203
Change-Id: I09ba46d2e102e7f2c4ef9a72bf38dedc1346364f