magma_dump from master cannot correctly read 7.2 files

As discussed with Apaar Gupta on Slack, current master magma_dump silently fails to read data from a 7.2.0 magma file:

• magma_dump from neo (7.2) - can read a 7.2 file ok:

  ~/repos/couchbase/server/neo/build-debug/magma/magma_dump magma.2 --kvstore 1002 --docs-by-seq 7211 --meta | head -n3

  {"Key":{"ascii":"_collection","cid":2927,"ns":1},"Meta":{"bySeqno":"7211","cas":"1683285288874147840","datatype":"0","deleteSource":"0","deleted":"0","exptime":"0","flags":"0","history_seconds":"1683285288","revSeqno":"1","valueSize":"64","version":"0"}}

  {"Key":{"ascii":"_collection","cid":2925,"ns":1},"Meta":{"bySeqno":"7215","cas":"1683285288874213379","datatype":"0","deleteSource":"0","deleted":"0","exptime":"0","flags":"2","history_seconds":"1683285288","revSeqno":"1","valueSize":"88","version":"0"}}

  {"Key":{"ascii":"_collection","cid":2912,"ns":1},"Meta":{"bySeqno":"7217","cas":"1683285288874278912","datatype":"0","deleteSource":"0","deleted":"0","exptime":"0","flags":"2","history_seconds":"1683285288","revSeqno":"1","valueSize":"80","version":"0"}}

• master magma_dump prints nothing against same file (and returns 0 - success):

  ~/repos/couchbase/server/source/build-debug-arm64/magma/magma_dump magma.2 --kvstore 1002 --docs-by-seq 7211 --meta | head -n3

  EOF

Attached a magma single shard from 7.2.0 (see MB-56763) to reproduce.