Fixes this error:
dav1d| Subproject dav1d finished.
gst-plugins-rs| WARNING: Subproject 'dav1d' did not override 'dav1d' dependency and no variable name specified
gst-plugins-rs| Dependency dav1d from subproject subprojects/dav1d-1.4.1 found: NO
subprojects/gst-plugins-rs/meson.build:382:14: ERROR: Dependency 'dav1d' is required but not found.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6436>