[STM32WLx] Update Rx interrupt example (#1272)

examples/STM32WLx/STM32WLx_Receive_Interrupt/STM32WLx_Receive_Interrupt.ino

@@ -154,8 +154,5 @@ void loop() {
       Serial.println(state);
 
     }
-
-    // put module back to listen mode
-    radio.startReceive();
   }
 }