'Setting has an invalid type, expected "string". Fix in JSON.' in settings

Issue Summary

Several options in settings have red warning boxes with the text "Setting has an invalid type, expected "string". Fix in JSON."

I think they have no harm, just look ugly in settings.

In "settings.json" these options are not assigned, they have default values.
In the file "package.json" in the repository, these options are assigned to null but their type is string. Like this:

"cmake.installPrefix": {
    "type": "string",
    "default": null,
    "description": "%cmake-tools.configuration.cmake.installPrefix.description%",
    "scope": "resource"
}

Options that shows red boxes:

• cmake.copyCompileCommands
• cmake.ctestPath
• cmake.installPrefix
• cmake.platform
• cmake.toolset

Platform and Versions

• Operating System: Arch Linux
• CMake Version: 3.17.2
• VSCode Version: 1.45.0
• CMake Tools Extension Version: 1.3.1
• Compiler/Toolchain: GCC 9.3.0

Start with the listed setting declarations in package.json and compare them with the corresponding defaults in settings.json. Check how VS Code renders these five settings and verify that the red invalid-type warnings disappear without changing their intended defaults.