[_] handle case when self is kicked out but not during login

[TamaraFinogina]

Description

This PR adds a fix for kick-outs to work + small type check fix

Motivation and Context

Jitsi has never handled a case where the server kicks out an already logged-in user due to duplicated login. They either kick out a duplicated user that is attempting to log in, or a moderator kicks out a meeting participant. So, our case was returning an undefined participant. Added a quick fix, similar to the one Jitsi has.

How Has This Been Tested?

unit tests, QA in local

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.