Mobile v2.36 Docs: Add self-management capability to channel members

[Combs7th]

Updates documentation to reflect PR #9301 / MM-66375 bug fix in mobile v2.36+

• Added "Manage your own membership" section with mobile-specific workflow
• Users can now manage their own roles/membership from Manage Channel Members screen
• Applies when user has permission to manage members

Closes #8664

🤖 Generated with Claude Code

[Combs7th]

@larkox - Do the above doc updates look accurate to you?

[github-actions]

Newest code from mattermost has been published to preview environment for Git SHA 197a9ff

[larkox]

@Combs7th The documentation is technically correct, but I am on the fence on whether it is worth it to add this particular thing to the documentation. Feels more like clutter than anything else. My point is:

• Mobile is, generally, up to date automatically. Not many people has older mobile versions
• This is a feature that was available already on web, this is just part of maintaining the parity between the two tools. Having this piece of documentation could imply mobile and web work differently.
• Managing your own membership / role is virtually the same as managing any other user, so extra documentation adds almost no value

I am going to approve this, in case you want to move forward with this, but please keep in consideration my comments in case you want to close this PR.

[github-actions]

Newest code from mattermost has been published to preview environment for Git SHA c4d3484

[wiersgallak]

@john-combs What if we were to combine the "Leave Channel" and "Manage Members" portion. Perhaps we can just add a note to the bottom of that section that states:

If you have permission to manage channel members, you can also leave a channel from View Info → Members → Manage by selecting your name. This setting also allows you to manage your role if that permission is also granted