Function delete_profile_field_route 

pub(crate) async fn delete_profile_field_route(
    __arg0: State<State>,
    __arg1: ClientIp,
    body: Args<Request>,
) -> Result<Response>

DELETE /_matrix/client/unstable/uk.tcpip.msc4133/profile/{user_id}/{field}

Deletes the profile key-value field of a user, as per MSC4133.

This also handles the avatar_url and displayname being updated.