Fix team managment (#121)

Fix member/admin button overflowing

Fix changing team member admin status

Fix adding team members

Co-authored-by: kolaente <k@knt.li>
Reviewed-on: https://kolaente.dev/vikunja/frontend/pulls/121

src/services/teamMember.js

@@ -6,7 +6,7 @@ export default class TeamMemberService extends AbstractService {
 	constructor() {
 		super({
 			create: '/teams/{teamId}/members',
-			delete: '/teams/{teamId}/members/{id}', // "id" is the user id because we're intheriting from a normal user
+			delete: '/teams/{teamId}/members/{username}',
 		});
 	}