BUG: Add CPACK_NSIS_PACKAGE_NAME to the list of CPack variables that CMake overrides. We use the same value as the CPack-provided default, but do it here such that configuring with an older CMake will still give us this new variable. Necessary so that the CMake release process works with the new variable: CMake is configured with a previous CMake, but packaged with the freshly built CPack. (This fix is necessary because the fix for issue #8682 caused the side effect of having an empty CPACK_NSIS_PACKAGE_NAME for the CMake nightly package.)