fix extern variable

Author: fabik111

src/ArduinoIoTCloud.h

@@ -250,10 +250,10 @@ class ArduinoIoTCloudClass {
 
 #if defined(ARDUINO_SAMD_MKRGSM1400) || defined(ARDUINO_SAMD_MKRWIFI1010) ||  defined(ARDUINO_SAMD_MKR1000) || defined(ARDUINO_SAMD_NANO_33_IOT)
   #include "ArduinoIoTCloudTCP.h"
-  extern ArduinoIoTCloudTCP ArduinoCloud;
+  
 #elif defined(ARDUINO_SAMD_MKRWAN1300) || defined(ARDUINO_SAMD_MKRWAN1310)
   #include "ArduinoIoTCloudLPWAN.h"
-  extern ArduinoIoTCloudLPWAN ArduinoCloud;
+  
 #endif
 
 #endif