Fix BluetoothDevicesSlice doesn't appear issue.

In Settings cold launch, it took a little bit time to do Bluetooth
profile service connection. If we get the Bluetooth device connected
state before service connected, the return value will always false.
This behavior caused BluetoothDevicesSlice can't collect media devices
immediately in cold launch, therefore, no data to build this card.

According latest discussion, this card is used for all Bluetooth
devices, so we don't need to wait profile to get specific devices.
Hence, update design to show all connected Bluetooth devices and
keep the operations are the same with Settings > Connected devices.

Fixes: 124462139
Test: visual, robotests
Change-Id: I1418e09f2cdc7ea8beaa73d7a59440ee2baae63b