GeometryScript: explicitly clear SectionInfoMap in CopyMeshToStaticMesh() instead of clearing entries one at a time, which is wrong if only some sections are in the map
#rnx
#jira UE-138808
#preflight 61df651f9c1e5c90b61a54ad
#ROBOMERGE-AUTHOR: ryan.schmidt
#ROBOMERGE-SOURCE: CL 18597446 in //UE5/Release-5.0/... via CL 18597457 via CL 18597465
#ROBOMERGE-BOT: STARSHIP (Release-Engine-Test -> Main) (v899-18417669)
[CL 18597480 by ryan schmidt in ue5-main branch]