Fixes an issue where the Generate PolyGroups algorithm would randomly create very large, oddly-shaped regions in cases where the settings would normally generate many single-triangle regions.
#rb rinat.abdrashitov
[CL 28488198 by jimmy andrews in ue5-main branch]
- add FPolygroupLayer struct which is basically an identifier for a Polygroup layer, ie either the default mesh layer or one of the extended attribute layers
- add FPolygroupsGenerator::FindPolygroupsFromHardNormalSeams()
- add option to FPolygroupsGenerator::FindPolygroupsFromFurthestPointSampling() to constrain generation relative to an input polygroup set, ie only subdivide existing polygroups
- FMeshRegionGraph::BuildFromComponents now takes optional are-triangles-connected predicate, to allow links in graph to be disabled
- FPatchBasedMeshUVGenerator can now optionally generate new UV islands relative to an input Polygoup set, via new GroupConstraint input
#rb david.hill
#rnx
#jira none
#preflight 6142106e568b3a0001dbc2d0
#ROBOMERGE-AUTHOR: ryan.schmidt
#ROBOMERGE-SOURCE: CL 17522255 in //UE5/Main/...
#ROBOMERGE-BOT: STARSHIP (Main -> Release-Engine-Test) (v870-17433530)
[CL 17522278 by ryan schmidt in ue5-release-engine-test branch]
