Display "see all" option when bluetooth is off

- This CL before, Bluetooth settings will hide the "see all"
  option when bluetooth is off. For the UX improvement, this
  CL will show the "see all" button when bluetooth is off. And
  turn on the BT when user press "see all" button to let user to
  quick pair their disconnected devices.
- Update and add test case

Bug: 147150367
Test: make -j42 RunSettingsRoboTests
Change-Id: I7a1451a36a31253b6be2203341bea4e59fed7c2b