Skip Xcode installation check with QT_NO_XCODE_MIN_VERSION_CHECK

We can use QT_NO_XCODE_MIN_VERSION_CHECK to skip the Xcode version check, but since https://github.com/qt/qtbase/commit/a13bfec63df2cf206e354ab56fc017a1f0eb8f6d (6.10) / https://github.com/qt/qtbase/commit/09f68238d47dae6b531a6685deb74202e910078f (6.9) the check still fails if Xcode is not installed at all. I'd like to request the variable to also skip this check.

For our purposes, a full Xcode installation is not required, so we only installed the command-line tools as that saves a lot of space. We'd prefer not having to define QT_NO_APPLE_SDK_AND_XCODE_CHECK as this will skip the platform SDK check as well.