Send invitation for specific role

[SimoneZaza]

Description

As an admin, I want to invite people directly as admin or lead, instead of waiting for them to accept the invitation before I can promote them to be an admin or lead.

Acceptance criteria

• [ ] In Alkemio user invitation dialog, add dropdown for role as per design (same as for email invite)
• [ ] In email invitation dialog, add dropdown for role as per design (same as for email invite)
• [ ] Roles that can be selected, in this order:
• Member
• Admin
• Lead

Additional Context

Related server issue: #3911 https://www.figma.com/design/y7EcC4ImZuFvbckKNdE1Vt/Invitations?node-id=97-2&t=8gQTybbc5S1NAn48-1

Areas that will be affected

To be added during the refinement