Support Cross-folder deployment in new Deployment Pipeline UI

In the new Deployment Pipeline, it is currently not supported to deploy multiple items across folders, nor does the filters apply across folders.

This creates inconsistency with the filter and search experience in Workspaces.

Additionally, being able to select items across folders for deployment is critical to avoid several, smaller deployments. Until this is supported, most of our deployment routines will likely have to use the old UI to avoid splitting up coherent deployments to several smaller ones. Otherwise, it would make deployment even less efficient and more difficulty to relate deployments to specific PRs for instance for lineage/deployment versioning and traceability.