kcms/desktoptheme: find metadata.json when loading ThemesModel
Before this commit ThemesModel only finds metadata.desktop, but after KF5.94, the default theme metadata files have been ported to json format. BUG: 453830
Before this commit ThemesModel only finds metadata.desktop, but after KF5.94, the default theme metadata files have been ported to json format. BUG: 453830
mentioned in commit f77b7284
·mentioned in commit f77b7284