[PATCH 1/3] h266parser: Fix overflow when parsing subpic_level_info

[PATCH 1/3] h266parser: Fix overflow when parsing subpic_level_info

1. non_subpic_layers_fraction, ref_level_idc and ref_level_fraction_minus1
   fields should not have the GST_H266_MAX_SUBLAYERS limitation.
2. Should check max_sublayers_minus1, no more than GST_H266_MAX_SUBLAYERS-1

Fixes ZDI-CAN-27381, CVE-2025-6663

Closes: https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/4503
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/9295>

Gbp-Pq: Name 0001-h266parser-Fix-overflow-when-parsing-subpic_level_in.patch