Revert "Bluetooth: Always request for user confirmation for Just Works (LE SC)"

This reverts commit ffee202a.

The commit "Bluetooth: Always request for user confirmation for Just
Works" prevents BLE devices pairing in (at least) the Raspberry Pi OS
GUI. After reverting it, pairing works again. Although this companion
commit ("... (LE SC)") has not been demonstrated to be problematic,
it follows the same logic and therefore could affect some use cases.

If another solution to the problem is found then this reversion will
be removed.

See: https://github.com/raspberrypi/linux/issues/4139



Signed-off-by: Phil Elwell <phil@raspberrypi.com>