MM-22372: fix unhandled exception when exporting to CSV. (#13864)

* MM-23272: fix unhandled exception

* MM-22372: removed extra log command

* MM-22372: fix merge conflict

cmd/mattermost/commands/export.go

@@ -153,7 +153,7 @@ func buildExportCmdF(format string) func(command *cobra.Command, args []string)
 		}
 
 		if a.MessageExport() == nil {
-			CommandPrettyPrintln("MessageExport feature not available")
+			return errors.New("message export feature not available")
 		}
 
 		err2 := a.MessageExport().RunExport(format, startTime)