Updated mmctl export create command flag (#25474)

* Updated export create flag

* Update server/cmd/mmctl/docs/mmctl_export_create.rst

* Updated mmctl export create command flags

server/cmd/mmctl/docs/mmctl_export_create.rst

@@ -21,8 +21,8 @@ Options
 ::
 
   -h, --help                        help for create
-      --include-archived-channels   Set to true to include archived channels in the export file.
-      --no-attachments              Set to true to exclude file attachments in the export file.
+      --include-archived-channels   Include archived channels in the export file.
+      --no-attachments              Exclude file attachments from the export file.
 
 Options inherited from parent commands
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~