add nil check for main SensorData subtables (but not values in those subtables)

main.lua

@@ -771,6 +771,10 @@ function UpdateGlobalThrust()
 
     local dt = GetDeltaTime()
 
+    if SensorData.Gimbal == nil or SensorData.Altitude == nil or SensorData.Velocity == nil then
+        print("ERROR: One or more of SensorData is nil. Cannot update thrust.")
+        return
+    end
     
     local throttleOutput = PIDs.AltitudePID:update(Config.Autopilot.AutopilotDesiredAltitude or 0, SensorData.Altitude.Altitude or 0, dt)