CLI: Add support for LCG Views

[ftorrresd]

When using correctionlib from a LCG View, correction config return invalid paths.

Example:

$ source  /cvmfs/sft.cern.ch/lcg/views/LCG_108/x86_64-el9-gcc15-opt/setup.sh
$ correction config --cflags --libdir                                                                          
-std=c++17 -I/cvmfs/sft.cern.ch/lcg/views/LCG_108/x86_64-el9-gcc15-opt/lib/python3.12/site-packages/correctionlib/../../../include /cvmfs/sft.cern.ch/lcg/views/LCG_108/x86_64-el9-gcc15-opt/lib/python3.12/site-packages/correctionlib/../../../lib
$ ls /cvmfs/sft.cern.ch/lcg/views/LCG_108/x86_64-el9-gcc15-opt/lib/python3.12/site-packages/correctionlib/../../../include
ls: cannot access '/cvmfs/sft.cern.ch/lcg/views/LCG_108/x86_64-el9-gcc15-opt/lib/python3.12/site-packages/correctionlib/../../../include': No such file or directory

This PR attempts to fix this by checking for invalid paths, before they are returned and when it happens, assume it is a LCG View setup.

[ftorrresd]

Must confess: I could not find a way to test this PR locally. current_lcg_view_path(...) (definition) was tested, but not integrated with correctionlib under a LCG setup.

[nsmith-]

The LCG views previously had issues with moving library files around, I reported it in https://its.cern.ch/jira/browse/SPI-2696 and it was patched in https://gitlab.cern.ch/sft/lcgcmake/-/merge_requests/2652 though I'm not sure as of which LCG version. I guess this patch is now bad?

[ftorrresd]

The LCG views previously had issues with moving library files around, I reported it in https://its.cern.ch/jira/browse/SPI-2696 and it was patched in https://gitlab.cern.ch/sft/lcgcmake/-/merge_requests/2652 though I'm not sure as of which LCG version. I guess this patch is now bad?

I think so...

[nsmith-]

So, it would be better to undo that patch / understand why it no longer is useful than to workaround it here, since its an upstream bug. Would you be willing to make an issue on the JIRA and follow-up?