Parsing TwitterTextEntityScreenName fails

[Kyome22]

Describe the bug
If the user enters an Emoji with a number in a box such as 1️⃣ without any space after the screenName starting with @, the screenName parsing fails.

To Reproduce
Steps to reproduce the behavior:

1. Go to tweetdeck.twitter.com and open the text field for a new tweet.
2. Type @hello1️⃣ and post the tweet.
3. Check the tweet in the timeline.
4. See the garbled text like the attached image.
   

Expected behavior
The screenName is parsed correctly and the text is not garbled.

Environment
I see this phenomenon when using TweetDeck in Chrome for macOS.

Additional context
This problem also exists in the Objective-C implementation of twitter-text.