✨ Constraint importing event into a different major version

[eselimsen]

Parent issue: https://github.com/sequentech/meta/issues/11114

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[BelSequent]

Now that you mentioned on the ticket the thing about the BACK_TRACE, I thought there is an opportunity to make this more user friendly:

Then endpoint already supports returning an error text + a message field, which will make more sense for a business logic like this instead of a raw error. If we do this way there is no backtrace on the UI.

check_version_compatibility does not need to return Anyhow (the backtrace), because the only invokation there is extract_semver which returns an Option, so a simple error with the text would serve and you can match this into the error field.

Unfortunately check_version_compatibility lives inside get_election_event_schema, which needs backtrace, but there is a quick workaround: I would just extract that encapsulation, and maybe add map_err() to the failure points with helpful messages.