ext_external_objects/framework: fix dstAccessMask of barriers

The barriers we use at the end of renderpass should use dstAccessMasks that are supported by the pipeline stage. Fixed the function that selects the access mask. Documentation: https://www.khronos.org/registry/vulkan/specs/1.2-extensions/html/vkspec.html#synchronization-access-types-supported

Signed-off-by: Eleni Maria Stea elene.mst@gmail.com