This patch fixes broken connections and effect strips which would arise
in some cases when trying to split connected strips with effects.
This happened in case an effect strip was being split -- first, its
effect chain would be added to a VectorSet of seqs, but then, only the
connected strips of the original seq (in this case the effect strip)
would be added to the VectorSet. Fix by iterating over the entire list
and adding connected strips.
Additionally:
- Add a final SEQ_iterator_set_expand() for SEQ_query_effect_chain() in
case these connected strips had effects themselves.
- Move the seq_edit_split_operation_permitted() check after the entire
chain is evaluated to avoid bugs w/ locked strips being editable
before.
Pull Request: https://projects.blender.org/blender/blender/pulls/128670
e3f9d210d1