[mlir][transform] TrackingListener: Improve dead handles detection (#74290)

The tracking listener should not report op replacement errors for
payload ops that are not mapped to any live handles. The handle liveless
analysis did not work properly with transform IR that has named
sequences.

A handle is live if it has a user after the transform op that is
currently being applied. With named sequences, we need to maintain a
stack of currently applied transform ops. That stack already exists
(`regionStack`), the only thing that's missing is the current transform
op for each stack frame.

This commit fixes #72931.