at least with Element Web: they still rely on the
"redacts" top level key. it was reported that
federated redactions were not working for v11 rooms
with conduwuit. after adding back the top level
key when appending a PDU to the timeline, they
now work again.
spec below says to continue adding the top level
key for compatibility with older clients.
https://spec.matrix.org/v1.9/rooms/v11/#moving-the-redacts-property-of-mroomredaction-events-to-a-content-property
Signed-off-by: strawberry <strawberry@puppygock.gay>