ISM Metadata file too short for ltv testvectors for 3 and 4 ISMs

When running

./IVAS_cod -ism 4 ivas-pc-testfiles/ltvISM1.csv ivas-pc-testfiles/ltvISM2.csv ivas-pc-testfiles/ltvISM3.csv ivas-pc-testfiles/ltvISM4.csv 96000 48 ivas-pc-testfiles/ltv48_4ISM.wav bit

with the files from the testfile repo, the encoder crashes with

Error (File read error) while reading ism metadata from: /Users/knj/Documents/IVAS/PC/ivas-pc-testfiles/ltvISM1.csv

The reason is that the csv files have too few lines to support the whole wav file. In our automated tests, this does not show up since we always limit the long testvectors for runtime reasons to 2 minutes. Thus, it is not really critical to fix this, but it sparked a bit of confusion when using the files locally.