[FIX] Abandoned feature: deletion of the line 'chat' => 'tiki-chat.php' from route.php to avoid error message

every time a user enters the word "chat" in the url just after logging in to tiki to access the chat function, it generates an error because the chat functionality has already been abandoned in Tiki. to resolve the warning that is displayed to the user, I deleted the line that pointed to the tiki-chat.php file which no longer exists.