gstreamer-plugin: fails to build since 3.0.0

Regressed by !2377 (merged). Part of this repo (and gst-plugins-bad repo) but not covered by CI. Found via downstream package.

$ cd gstreamer-plugin
$ cmake -G Ninja -B _build
$ cmake --build _build
[...]
../gstsvtav1enc.c:538:32: error: no member named 'high_dynamic_range_input' in 'struct EbSvtAv1EncConfiguration'
  538 |         svtav1enc->svt_config->high_dynamic_range_input        = true;
      |         ~~~~~~~~~~~~~~~~~~~~~  ^
../gstsvtav1enc.c:541:32: error: no member named 'high_dynamic_range_input' in 'struct EbSvtAv1EncConfiguration'
  541 |         svtav1enc->svt_config->high_dynamic_range_input = false;
      |         ~~~~~~~~~~~~~~~~~~~~~  ^