BUG: 291850 - Use KFileDialog::getExistingDirectoryUrl() instead of...

BUG: 291850 - Use KFileDialog::getExistingDirectoryUrl() instead of KDirSelectDialog::selectDirectory() which clearly has some platform issues on
Windows.

This results in the same behaviour on Linux but on Windows it means that the native directory selection dialog will be opened.
I think this solution is better then waiting for a fix in kdelibs on Windows for the following reasons:
1. In the docs of KDirSelectDialog::selectDirectory()  it is stated that it's equivalent with KFileDialog::getExistingDirectoryUrl()
2. The native directory selection dialog works on Windows while the KDE dialog needs a patch to avoid an infinite loop (will contact the KDE on
Windows team regarding this)
(cherry picked from commit c67cd7ac)