Unfortunately lupdate now misdetects the context wrt namespace differently than it did in Qt 6.9.2

In Qt Creator we use one "Tr" struct per plugin to consolidate all translations/tr-calls from that plugin. The struct is always called "Tr", has the "Q_DECLARE_TR_FUNCTIONS" macro and lives in the plugin namespace. E.g.

https://code.qt.io/cgit/qt-creator/qt-creator.git/tree/src/plugins/coreplugin/coreplugintr.h
https://code.qt.io/cgit/qt-creator/qt-creator.git/tree/src/plugins/cppeditor/cppeditortr.h

Normally we only use the "Tr" struct from that plugin, but sometimes a plugin uses a translation from a different plugin, e.g. some project management plugins use some common translations from the ProjectExplorer plugin.

With Qt 6.9.2 the following situation fails to correctly determine the correct translation context/namespace:

#include "cppeditortr.h"

#include <coreplugin/coreplugintr.h>

using namespace Core;

namespace CppEditor::Internal {
...
    Tr::tr("this should be CppEditor::Tr")
...
    ::Core::Tr::tr("this is Core::Tr")
...
} // namespace CppEditor::Internal

In this case the plain Tr::tr should be resolved as CppEditor::Tr::tr, but the translations is wrongly assigned to the Core::Tr context.

Qt 6.9.1 still works. I guess this was an unnoticed side-effect of the fix for QTBUG-136768