Enable location in NearbyDevicesPermissionTest

Location services must be enabled on the device to perform unfiltered
Bluetooth scans.

As a result, since this test isn't enabling location, it was at the
mercy of whether or not a previous test enabled/disabled it. The result
was that the test appeared flaky.

Bug: 295967456
Test: atest NearbyDevicesPermissionTest
Change-Id: I9c5649bdf7ff96feebf3647b287b8bf9ac574c73