loadSimulationsFromSnapshot(): support snapshots containing PK-Sim modules (PKSim.Starter.dll not shippable)

Summary

Snapshots that contain PK-Sim modules cannot be converted by loadSimulationsFromSnapshot() in the headless R package: PKSim.Starter.dll cannot be shipped in inst/lib because it references UI/Presentation assemblies.

This limitation was documented in the commit message of #1950 (32676073) but was missing from user-facing docs; reported by @Yuri05 in the v13 merge PR review (#1958, comment of 2026-08-14). The NEWS entry for loadSimulationsFromSnapshot() now mentions the limitation.

Scope of this issue

Tracking issue for lifting the limitation:

• Upstream work in PK-Sim and MoBi (factoring the snapshot/module conversion out of PKSim.Starter so it becomes available to headless consumers) — tracked there as follow-up to the #1950 work.
• Once upstream support lands: bump the bundled assemblies, extend the tests to a snapshot containing PK-Sim modules, and drop the limitation note from NEWS and the snapshots vignette.

Not a 13.0 release blocker (documented limitation), but should stay visible until resolved.

First confirm that the upstream PK-Sim and MoBi work has made snapshot/module conversion available to headless consumers. Then update the bundled assemblies, extend the loadSimulationsFromSnapshot() tests with a snapshot containing PK-Sim modules, and remove the limitation note from NEWS and the snapshots vignette.