use --install in installation tests on Windows

[bratpiorka]

This is a fix for the failing test_installation.py on Windows, introduced by #1285. The failures are related to the --target install command, which is not properly recognized on Windows. This pull request reverts the installation command to the previous version, which uses --install for Windows.

example of passed Windows Ninja job: https://github.com/oneapi-src/unified-memory-framework/actions/runs/14972212328/job/42055589833?pr=1310

and Windows NMake job: https://github.com/oneapi-src/unified-memory-framework/actions/runs/14972212328/job/42055589878?pr=1310

full nightly run: https://github.com/oneapi-src/unified-memory-framework/actions/runs/15117728112

[bratpiorka]

@ldorau @lukaszstolarczuk ready for re-review