Request: Add lock_permissions to PATCH/channels/{channel.id}

[almostSouji]

As #1776 points out there is a lock_permissions field when setting channel positions. As a quality of life feature this would be nice to have for the Modify Channel endpoint.

It already has parent_id, allowing setting a new parent, allowing it to lock permissions to it seems to be quite a natural expansion.

Sidenote: yes, i am aware that we can pass the parents overwrites in order to lock, this is not the point of this request

[almostSouji]

I do hate to bump things, but since #1776 is now merged I'd love to refactor how we handle channel moving, which would be much, much easier to handle if this were to become a thing!