Without CMAKE_INSTALL_PREFIX, Arcane is installed in build directory #2204
Description
When Arcane and Alien are build at the same time, without CMAKE_INSTALL_PREFIX being defined in CMake configure, Arcane is installed in build/_common/build_all/alien/ArcaneInterface/install/1.0.0.
In Codecov CI, CMAKE_INSTALL_PREFIX is not specified, so the installation directory is displayed in the AlienPlugin config part ( https://github.com/arcaneframework/framework/actions/runs/17662229870/job/50197478144#step:10:1198 ).
The CMake part causing this bug can be found here : https://github.com/arcaneframework/framework/blob/main/alien/ArcaneInterface/cmake/build-system/LoadBuildSystem.cmake#L100