The older code attempted to be clever and sync component additions and
removals with what the message edit is doing. In some cases, this led
to the re-creation of those components causing lost attributes to be
dropped such as `_rendered_row` which would mess up handling of view
weights.
Instead of recreating the children list every time and keeping track
of additions and removals, this change just updates the old state with
the new state while ignoring any new or removed additions. This should
work fine in theory due to additions or removals already being present
before editing the View instance in the first place.
Closes#7231#7511
e198a0e7e6