Fix reading of Plutus V2 cost models with different lengths in AlonzoGenesis in different eras #3089

Job	Run time
build (3.10.2.0, 9.6.4, macos-latest, bash)	29m 54s
build (8.10.7, 3.10.2.0, ubuntu-latest, bash)	6m 40s
build (8.10.7, 3.10.2.0, windows-latest, C:/msys64/usr/bin/bash.exe -e {0})	9m 24s
build (9.6.4, 3.10.2.0, ubuntu-latest, bash)	5m 4s
build (9.6.4, 3.10.2.0, windows-latest, C:/msys64/usr/bin/bash.exe -e {0})	6m 42s
build (9.8.1, 3.10.2.0, windows-latest, C:/msys64/usr/bin/bash.exe -e {0})	5m 33s
build (9.8.1, 3.10.2.0, ubuntu-latest, bash)	4m 43s
build-complete	1s
release	0s
	1h 8m 1s

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