For all twitter users whose Tweets are protected gives 500 error
I am using local nitter instance. All users who have protected their tweets or no tweets or user suspended gives 500 error(user not found) while fetching it from rss.  Also all users who doesnt have any tweets also gives user not found. It would be great to have the error  precise for rss also which should be helpful to specify as "tweets are protected for this user" or "No items found" which is visible in the page without converting to rss.


Eg: 
https://nitter.net/hannelorekraft gives correct response
https://nitter.net/hannelorekraft/rss gives User "hannelorekraft" not found
https://twitter.com/hannelorekraft

![image](https://github.com/zedeus/nitter/assets/87175483/c52ac78a-2601-4e15-94a9-2a09c31d839f)

