QtQuick.Controls is resolved at runtime to be org.kde.desktop

qmlcachegen can't follow that though, so it can't precompile
QtQuick.Controls usages.

Here we know that we are using the local Popup in the end, so use it
directly and make qmlcachegen happier.

Use Action from Templates since that is only defined there.

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Inspired by patches from Nicolas Fella <nicolas.fella@gmx.de>