Add tests for 'is typing...' status in channels

[kakRostropovich]

Add tests for this PR.

I've added this PR to comply with this project structure and maybe work with us if you're interested.

About PR:

• Create a test suite inside the channel tests file. It contains some tests for the "[username] is typing..." feature
• Work with the current user and 2 temporary users. I've named them Alice and Bob, it's just for fun, I can rename them to user1 and user2 if necessary.
• Use existing methods for now. I think it's possible to create more page object's methods in the future to make my code and the code in this file more compact. I will be happy to do this if we continue to connect.
• I decided to group tests in this case, it doesn't look atomic enough, but I need to check, maybe I will be better to remove nested beforeEach and redesign it.

I hope this PR will be helpful for the team.
I'm going to keeping it in Draft, want to check test running in CI and maybe fix problems.

[kakRostropovich]

Request will be reopened without a fork