Backport of "libs: enc: h265: reset num_ref_idx_l1_active_minus1 when low delay B." into 1.16
Backport of !91 (merged) "libs: enc: h265: reset num_ref_idx_l1_active_minus1 when low delay B.".
Commits:
- bc1ca96e libs: enc: h265: reset num_ref_idx_l1_active_minus1 when low delay B.