Implemented Display banned members in the Manage Group page

I'm not sure if this is intended, but it's pretty annoying and I don't know why it works like this. It doesn't sound like a bug either as I've had other groups in some forums that use MyBB and it's always been the same, so I thought this would be better suited as a suggestion instead.

I've had people I wanted removed from the group while they were still banned and couldn't - even though they don't show up on the member list they're still there for some reason, unable to be removed. And it gets worse when you have permed members showing up on groups they were previously in that have changed ownership and niche, such as Yodasi (got permed when he was a Devils member, unbanned and is still on the group, but it's Challenge now).

That's it, I guess! Thank you for reading. >w<