PanelDue: Make checksums optional

Some displays which emulate PD firmware do not use checksums.

Signed-off-by:  Eric Callahan <arksine.code@gmail.com>

moonraker/plugins/paneldue.py

@@ -139,6 +139,7 @@ class PanelDue:
         self.last_gcode_response = None
         self.current_file = ""
         self.file_metadata = {}
+        self.enable_checksum = config.getboolean('enable_checksum', True)
 
         # Initialize tracked state.
         self.printer_state = {
@@ -308,6 +309,7 @@ class PanelDue:
             await self.klippy_apis.emergency_stop()
             return
 
+        if self.enable_checksum:
             # Get line number
             line_index = line.find(' ')
             try:
@@ -341,6 +343,8 @@ class PanelDue:
                 raise PanelDueError(msg)
 
             await self._run_gcode(line[line_index+1:cs_index])
+        else:
+            await self._run_gcode(line)
 
     async def _run_gcode(self, script):
         # Execute the gcode.  Check for special RRF gcodes that