RoomVC: Remove Jitsi slider for DMs

[ismailgulek]

Fix #4706

[manuroe]

We cannot merge this PR yet because there is a bug in scalar where you cannot remove a Jitsi widget. So, if we hide this button, the user won’t be able to remove the widget anymore.

[stefanceriu]

@manuroe @ismailgulek do we know if this is still blocked? If so can we link it to something?

[manuroe]

Unfortunately, we do not have other link to share. I think nobody have worked on scalar since a long time.

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