fix: "reply to message" now takes usernames with @'s & commas into consideration

[KleberPF]

This fixes not being able to reply to an user if you are already mentioning them before the reply action. Here are the possibilities:

Regular mesage

Before reply action

After reply action

Mentioning user with a comma

Before reply action

After reply action

Mentioning user without a comma

Before reply action

After reply action

Mentioning user with a comma and with text after it

Before reply action

After reply action

Mentioning user without a comma and with text after it

Before reply action

After reply action

Fixes #5171

[Felanbird]

- Bugfix: Fixed an issue where you had to click the `reply` button twice if you already had that users @ in your input box. (#5173)

I like this entry because I noticed it when testing the original report, and it feels possible that this is the problem users saw

[pajlada]

Thank you!
I added some unit tests, if you can think of any additional unit tests that should or should not work, feel free to add those