Plane: do not use guided waypoint for loiter location

Currently this waypoint is set 10,000m away by the avoidance behaviour

Instead, immediately enter loiter mode

ArduPlane/avoidance_adsb.cpp

@@ -137,11 +137,18 @@ void AP_Avoidance_Plane::handle_recovery(RecoveryAction recovery_action)
             case RecoveryAction::RESUME_IF_AUTO_ELSE_LOITER:
                 if (prev_control_mode_number == Mode::Number::AUTO) {
                     plane.set_mode(plane.mode_auto, ModeReason::AVOIDANCE_RECOVERY);
+                } else {
+                    // let ModeAvoidADSB continue in its guided
+                    // behaviour, but reset the loiter location,
+                    // rather than where the avoidance location was
+                    plane.set_guided_WP(plane.current_loc);
                 }
-                // else do nothing, same as RecoveryAction::LOITER
                 break;
 
             default:
+                // user has specified an invalid recovery action;
+                // loiter where we are
+                plane.set_guided_WP(plane.current_loc);
                 break;
             } // switch
         }