Only check latest stable firmware one time

src/Vehicle/Vehicle.cc

@@ -1343,7 +1343,8 @@ void Vehicle::_handleAutopilotVersion(LinkInterface *link, mavlink_message_t& me
         nullStr[8] = 0;
         _gitHash = nullStr;
     }
-    if (_toolbox->corePlugin()->options()->checkFirmwareVersion()) {
+    if (_toolbox->corePlugin()->options()->checkFirmwareVersion() && !_checkLatestStableFWDone) {
+        _checkLatestStableFWDone = true;
         _firmwarePlugin->checkIfIsLatestStable(this);
     }
     emit gitHashChanged(_gitHash);

src/Vehicle/Vehicle.h

@@ -1504,6 +1504,7 @@ private:
     bool                _isROIEnabled   = false;
     Joystick*           _activeJoystick = nullptr;
 
+    bool _checkLatestStableFWDone = false;
     int _firmwareMajorVersion;
     int _firmwareMinorVersion;
     int _firmwarePatchVersion;