2.0.x Fix compiler warning (#9116)

Fix duplicate language define warning

Marlin/src/lcd/language/language_en.h

 #ifndef MSG_DAC_EEPROM_WRITE
   #define MSG_DAC_EEPROM_WRITE                _UxGT("DAC EEPROM Write")
 #endif
-#ifndef MSG_FILAMENT_CHANGE_HEADER
+#ifndef MSG_FILAMENT_CHANGE_HEADER_PAUSE
   #define MSG_FILAMENT_CHANGE_HEADER_PAUSE    _UxGT("PRINT PAUSED")
 #endif
 #ifndef MSG_FILAMENT_CHANGE_HEADER_LOAD