Issue #10650: Fix Curve Bend auto-preview

This patch attempts to resolve issue #10650 (closed).

During the GimpProcedureDialog port, newly generated widgets were connected to bender_global_notify (). However, GimpProcedureConfig was connected to it rather than a GtkWidget, which caused the function to return without updating since it did not have access to the BenderDialog object.

This patch connects the function to the individual rotate, smoothing, and anti-aliasing widgets to resolve the issue.