[qwen2 vl] fix packing with all attentions (#39447)
* fix qwen2 vl packing in FA2
* why? delete!
* qwen2-5-vl seems to work now
* update
* fix tests
* start by adapting FA2 tests
* add similar tests for sdpa/eager
* address comments
* why is this even in conditional model and not base model?
