Fix undefined E_LBL

Marlin/src/lcd/dogm/status_screen_DOGM.cpp

           lcd_put_u8str(estimation_x_pos, EXTRAS_BASELINE, estimation_string);
         }
         else if (elapsed_string[0]) {
+          extern const char E_LBL[];
           lcd_put_u8str_P(PROGRESS_BAR_X, EXTRAS_BASELINE, E_LBL);
           lcd_put_u8str(elapsed_x_pos, EXTRAS_BASELINE, elapsed_string);
         }