Sytest uses unspecced endpoint `DELETE /v3/directory/list/appservice/$network_id/$room_id`

[S7evinK]

(not sure if correct issue type)
Link to problem area:
https://spec.matrix.org/v1.4/application-service-api/#application-service-room-directories

sytest/tests/60app-services/06publicroomlist.pl

Lines 96 to 98 in ac50609

	do_request_json_for( $as_user,
	method => "DELETE",
	uri => "/v3/directory/list/appservice/$network_id/$room_id",

Issue
It looks like Sytest is using an undocumented endpoint DELETE /v3/directory/list/appservice/$network_id/$room_id?
Also mentioned in matrix-org/synapse#14178

Expected behaviour
Documented DELETE /v3/directory/list/appservice/$network_id/$room_id for appservices

[richvdh]

or better yet, rip it out of synapse and sytest?