[GH-19150] Remove strings in all channel types for constants (#19535)

Automatic Merge

store/sqlstore/post_store.go

@@ -2369,7 +2369,7 @@ func (s *SqlPostStore) GetDirectPostParentsForExportAfter(limit int, afterId str
 			sq.Eq{"p.DeleteAt": 0},
 			sq.Eq{"Channels.DeleteAt": 0},
 			sq.Eq{"Users.DeleteAt": 0},
-			sq.Eq{"Channels.Type": []string{"D", "G"}},
+			sq.Eq{"Channels.Type": []model.ChannelType{model.ChannelTypeDirect, model.ChannelTypeGroup}},
 		}).
 		OrderBy("p.Id").
 		Limit(uint64(limit))