Schema is incorrect

[MathMan05]

https://github.com/spacebarchat/server/blob/39b19d536cd7bedb437a2c8bee00355e48100bbf/src/util/schemas/ChannelModifySchema.ts#L26 This is incorrect, the type may not be any valid type, but must be of a subset, as one can't convert a channel into a dm or a channel into a category.