RM-344: Fix claim restoring the previous panel's team access after /switchpanel

[biast12]

RM-344

Description

Claiming on a panel with Support can view and Support can type enabled sent the channel's full permission overwrite list, read from the channel cache, with the claimer added. Right after /switchpanel that cache can still hold the previous panel's overwrites, so the claim gave the old panel's team access again and removed the new panel's team.

The claim now sets only the claimer's overwrite (EditChannelPermissions) and leaves every other overwrite untouched. It also skips the rename when the claimed name is the same as the unclaimed name. This covers /claim, the claim button, /transfer and dashboard claims.

Type of Change

• Bug fix
• New feature
• Breaking change

Testing

• two teams-only panels, panel B with Support can view + Support can type; open a ticket in A → /switchpanel to B → /claim → Team B keeps access, Team A has none

Checklist

• My code follows the style of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works