Add policy CMP0172 to set `CPACK_WIX_INSTALL_SCOPE` to `perMachine` by
default. Follow up commit 60661f6770 (CPack/WiX: Make InstallScope
configurable, 2023-11-07, v3.29.0-rc1~413^2) and commit 614100dbf6
(CPack/WiX: Restore default (missing) InstallScope from 3.28 and lower,
2024-06-05, v3.30.0-rc1~7^2~1).
Issue: #20962
Issue: #26029