appdata: Fix screenshots in the stable version
We updated the screenshots that will be used for GNOME 42, but we still need to keep the old screenshots working for the old version.
• attribute-invalid : <screenshot> width (1024) did not match specified (1043) [https://gitlab.gnome.org/GNOME/totem/raw/master/data/appdata/ss-videos.png]
• attribute-invalid : <screenshot> height (576) did not match specified (657) [https://gitlab.gnome.org/GNOME/totem/raw/master/data/appdata/ss-videos.png]
• attribute-invalid : <screenshot> width (1024) did not match specified (1043) [https://gitlab.gnome.org/GNOME/totem/raw/master/data/appdata/ss-player.png]
• attribute-invalid : <screenshot> height (576) did not match specified (657) [https://gitlab.gnome.org/GNOME/totem/raw/master/data/appdata/ss-player.png]