Update Space VC block (add invite button)

[SimoneZaza]

Description

As an admin, I want to be able to invite vc's directly from my Space Community page

Acceptance criteria

• [ ] "+ Invite Virtual Contributor" button at the top of the list of Virtual Contributors, like we do with the Subspaces hierarchy block in a Subspace (see screenshot below)

• [ ] This button should only be visible to people with the invite privilege (COMMUNITY_INVITE ?)

• [ ] The button opens the Invite VC dialog, same as it is now from Space > Settings> Community

• [ ] Remove margin between the VC cards in this block (see screenshot, the margin between title and vcs is fine, but there

Additional Context

Screen shots / UX designs / data that are relevant.