extrudeToRegionMesh always creates coupled baffles when extruding inter-zone edges

Functionality to add/problem to solve

extrudeToRegionMesh when running on multiple faceZones/sets extrudes any edge on multiple zones/sets into separate boundary faces. Instead it would be nice to have the edge extruded into a single internal face.

Target audience

E.g. cases with film models.

Proposal

Ignore zone info when extruding the edge such that inter-zone edges get handled exactly the same as normal edges.