video/gtk4: Add glib and gio dependencies

The gtk4 option enables the respective features, however without any dependencies on them the build would fail with:

none of the selected packages contains these features: gio/v2_74, glib/v2_74, did you mean: gst/v1_16, gtk/v4_6?

This notably happens when only building gtk4 (auto_features = disabled, gtk4 = enabled), which again makes sense for distros wanting to ship apps like Snapshot or Showtime.

Thus add the dependencies, ensuring the features are always matched.

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See also:

• https://gitlab.alpinelinux.org/alpine/aports/-/merge_requests/72448