fix(#2569): leave community settings

[kingalg]

Pull Request Checklist

• I have linked this PR to a related GitHub issue.
• I have added a description of the change (and Github issue number, if any) to the root CHANGELOG.md.

(Optional) Mobile checklist

Please ensure you completed the following checks if you did any changes to the mobile package:

• I have run e2e tests for mobile
• I have updated base screenshots for visual regression tests

@mike-kiss, those are the changes requested in the #2569 issue. I heard that you volunteered to check it! Thank you, and let me know if you have any questions or requests.

• Instead of modal, leaving a community is now a part of the sidebar.
• The "go back" button takes the user to the Settings.
• The "Leave Community" button inside the Leave Community section of Settings initiates the leaving community process and takes the user to the "Join Community" screen.