Resolves #14932
In Small Tiles, we update the preview whenever
the number of segments slider is dragged. However,
while we reacted to the slider moving, we actually grab
the number from the GimpProcedureConfig object.
As a result, there's a lag between the signal firing and the
config object updating, so we don't grab the latest change.
This patch alters the signal to run when "notify::num-tiles"
is called, resulting in the update function having the updated
number.
e27353216c