AP_NavEKF3: don't use disabled gyros in opticalflow takeoff detection

libraries/AP_NavEKF3/AP_NavEKF3_VehicleStatus.cpp

@@ -454,7 +454,7 @@ void NavEKF3_core::detectOptFlowTakeoff(void)
         Vector3f angRateVec;
         Vector3f gyroBias;
         getGyroBias(gyroBias);
-        bool dual_ins = ins.get_gyro_health(0) && ins.get_gyro_health(1);
+        bool dual_ins = ins.use_gyro(0) && ins.use_gyro(1);
         if (dual_ins) {
             angRateVec = (ins.get_gyro(0) + ins.get_gyro(1)) * 0.5f - gyroBias;
         } else {