Cannot link to Flann on Ubuntu 22.04

I cannot compile OMPL in Ubuntu 22.04 since 9efd7aad6fb (2023-10-26): `ld.lld: error: unable to find library -lflann::flann`.

To solve the issue, I used `${FLANN_LIBRARIES}` instead of `flann::flann`, i.e. I replaced `"$<$<BOOL:${OMPL_HAVE_FLANN}>:flann::flann>"` with `"$<$<BOOL:${OMPL_HAVE_FLANN}>:${FLANN_LIBRARIES}>"` in `src/ompl/CMakeLists.txt`.