Improvement and fixes to FTDI touch UI

- Fixed incorrect LCD text string
- Fixed incorrect refresh of filament change screens
- Allow host control via touch UI
- Updates to leveling menu
- Modified ExtUI::isPrinting() to check if the job timer is running
- Added ExtUI method to check whether a host print is paused

Marlin/src/lcd/extui/ui_api.cpp

@@ -972,7 +972,11 @@ namespace ExtUI {
   }
 
   bool isPrinting() {
-    return (commandsInQueue() || isPrintingFromMedia() || IFSD(IS_SD_PRINTING(), false));
+    return (commandsInQueue() || isPrintingFromMedia() || IFSD(IS_SD_PRINTING(), false)) || print_job_timer.isRunning() || print_job_timer.isPaused();
+  }
+
+  bool isPrintingPaused() {
+    return isPrinting() && (isPrintingFromMediaPaused() || print_job_timer.isPaused());
   }
 
   bool isMediaInserted() {