* Removed material override settings, since the editor can provide this functionality independently of tools.
* Removed Layout preview settings and support, since the editor visualizes the unwrap mesh already.
Known Issues:
* Editor currently doesn't handle unset UVs, causing crashes when using poly groups on meshes without poly groups
* Polygroup settings currently assume only one target. If multiple assets are loaded in the editor, polygroup settings will be removed and the default layer assumed for all loaded assets.
#rb semion.piskarev
#rnx
#ROBOMERGE-AUTHOR: nathan.mitchell
#ROBOMERGE-SOURCE: CL 18008730 in //UE5/Release-5.0/... via CL 18008752
#ROBOMERGE-BOT: STARSHIP (Release-Engine-Staging -> Release-Engine-Test) (v885-17909292)
#ROBOMERGE[STARSHIP]: UE5-Main
[CL 18008773 by nathan mitchell in ue5-release-engine-test branch]
