[BluetoothMetrics] This covers the case for Direct LE-ACL Connection

Success Rate as per go/bluetooth-le-connection-metrics.

Unit Tests:
- Successful
- Failure
- Timeout
- Cancellation

Test: atest bluetooth_test_gd_unit:LEConnectionMetricsRemoteDeviceTest --host
Change-Id: I7b8618c30d5f1e4dc5b9665e056934c2db888271
Merged-In: I7b8618c30d5f1e4dc5b9665e056934c2db888271