Describe the bug

The serial regression test p1rad, which runs SU2_CFD on TestCases/radiation/p1model/configp1.cfg, has a heap-buffer-overflow in CConfig::GetWall_Emissivity according to Clang's address sanitizer.

According to my printf debugging, nMarker_Emissivity is 2 and Wall_Emissivity is {"left", "right"} (matching the cfg file), but CRadP1Solver::BC_Marshak calls GetWall_Emissivity with the marker string "upper".

Bug report checklist

• Consulting the build instructions (https://su2code.github.io/docs_v7/Build-SU2-Linux-MacOS/).
• Looking for similar problems on GitHub or CFD-Online (https://www.cfd-online.com/Forums/su2/).
• Updating to the newest version of SU2 (either develop, master, or the pre-built executables https://su2code.github.io/download.html).

Desktop (please complete the following information):
Ubuntu 22.04 with Clang++ 16.0.6, MPI disabled, SU2 at current develop branch, commit f9f7a01.