systemtests: add perpendicular-flap solid-openfoam and solid-fenics cases (refs #448)

[AdityaGupta716]

Adds two missing case combinations for perpendicular-flap to the system tests, as listed in #448:

{fluid-openfoam, solid-openfoam} — added to openfoam_adapter_pr and release_test
{fluid-openfoam, solid-fenics} — added to fenics_test and release_test

Reference results for both combinations need to be generated via the CI workflow (generate_reference_results), as local execution on Apple Silicon fails due to a known GID conflict in the Ubuntu base image.
Refs #448

[AdityaGupta716]

Added {fluid-openfoam, solid-openfoam} and {fluid-openfoam, solid-fenics} to the system tests , covering two of the first-priority cases listed in #448 . Reference results need to be generated via CI. @MakisH happy to trigger that if you can point me to the right workflow.