Googletest is being downloaded even with tests disabled

In the configure stage of CMake builds when the googletest submodule is initialized for some reason CMake will attempt to download a release of googletest and populate its folder. This also happens with the `WITH_TESTS` and/or `BUILD_TESTS_BY_DEFAULT` set to `OFF`.
It is causing issues with building QT Creator in the flatpak builder sandbox as it cannot connect to the internet.
This does not happen with version 5.

See https://flathub.org/builds/#/builders/32/builds/68315