MM-24692: Add a since parameter to getGroups api (#14444)

* add a since parameter to getGroups api

* update for lint error

* when using since, return deleted groups as well.

* update flaky test, groups have same create time

Co-authored-by: mattermod <mattermod@users.noreply.github.com>

store/sqlstore/group_store.go

@@ -1144,9 +1144,16 @@ func (s *SqlGroupStore) GetGroups(page, perPage int, opts model.GroupSearchOpts)
 
 	groupsQuery = groupsQuery.
 		From("UserGroups g").
-		Where("g.DeleteAt = 0").
 		OrderBy("g.DisplayName")
 
+	if opts.Since > 0 {
+		groupsQuery = groupsQuery.Where(sq.Gt{
+			"g.UpdateAt": opts.Since,
+		})
+	} else {
+		groupsQuery = groupsQuery.Where("g.DeleteAt = 0")
+	}
+
 	if perPage != 0 {
 		groupsQuery = groupsQuery.
 			Limit(uint64(perPage)).