Updated generic handler to handle the lack of the text of the message

src/errors.rs

@@ -2,10 +2,6 @@
 #[error("No user info found")]
 pub struct NoUserInfo;
 
-#[derive(thiserror::Error, Debug)]
-#[error("Message text not found")]
-pub struct NoMessageText;
-
 #[derive(thiserror::Error, Debug)]
 #[error("Handler was already used")]
 pub struct HandlerUsed;