nimbus import spams logs on invalid era file

[arnetheduck]

WRN 2024-10-20 17:24:32.158+02:00 Failed to open era file                    path=/data/holesky/era/holesky-00033-c5c95e67.era error="count: too large"
WRN 2024-10-20 17:24:32.158+02:00 Failed to open era file                    path=/data/holesky/era/holesky-00033-c5c95e67.era error="count: too large"
WRN 2024-10-20 17:24:32.158+02:00 Failed to open era file                    path=/data/holesky/era/holesky-00033-c5c95e67.era error="count: too large"
ERR 2024-10-20 17:24:34.281+02:00 Failed to persist blocks                   error="Cannot update VmState to block 251450"

Even though the expected block is not available (due to a broken era file), the importer keeps trying logging thousands of warnings until it suddenly skips to some random block - on a corrupt era file, we should simply treat that as the end of the import