Add members (#7220)

* Add "Add members" modal

* Refactor into server user list

* Renaming and fixes

* Address feedback

* Add missing change

* Styling fixes for iOS

types/api/users.d.ts

@@ -103,6 +103,7 @@ type SearchUserOptions = {
 	team_id?: string;
 	not_in_team?: string;
 	in_channel_id?: string;
+	not_in_channel_id?: string;
 	in_group_id?: string;
 	group_constrained?: boolean;
 	allow_inactive?: boolean;