Currently, the turtle metadata parser treats unknown fields as errors, to support upcoming changes like adding version and compatible_version fields (as part of WT-16499), older builds need to be able to read turtle metadata even if it contains fields they don’t recognise. This change updates the parser to ignore unknown fields instead of failing, allowing the format to evolve without breaking older builds. This ticket also needs to modify where we check for data parsing, if we see checkpoint=... anywhere, we parse to the new format, otherwise use the legacy format.