Update a team

The team's icon: a Font Awesome solid icon name without the fa- prefix (headset, user-group) or one emoji. Empty string or null clears it. Checked by isValidTeamIcon (teamIcon.ts) in the controller.

Agents that take the team's new tickets first, in this order (teamBody.service checks them).

Working days of the team's people (teamBody.service keeps only members).

What the team handles, in a sentence: agents and Tasks route by it.

The team's lead: gets the team's unanswered asks. Must be a member.