Fix GRCBC subsonic inflow using wrong L index #4436

Job	Run time
Detect File Changes	10s
Lint Gate	1m 21s
Github (ubuntu, mpi, debug, true)	1h 26m 22s
Github (ubuntu, mpi, no-debug, true)	1h 32m 55s
Georgia Tech \| Phoenix (gpu-acc)	7s
Github (macos, mpi, no-debug, false)	1h 13m 57s
Oak Ridge \| Frontier (cpu)	4h 36m 45s
Oak Ridge \| Frontier (AMD) (gpu-omp)	5h 8m 26s
Github (macos, mpi, debug, false)	57m 48s
Github (ubuntu, mpi, debug, false)	2h 42m 35s
Oak Ridge \| Frontier (gpu-omp)	15h 7m 31s
Github (ubuntu, mpi, no-debug, false)	2h 18m 36s
Georgia Tech \| Phoenix (cpu)	10s
Github (ubuntu, no-mpi, single, no-debug, false)	28m 55s
Georgia Tech \| Phoenix (gpu-omp)	4s
Oak Ridge \| Frontier (gpu-acc)	15h 7m 31s
Oak Ridge \| Frontier (AMD) (cpu)	1s
	2d 2h 43m 14s

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