make `--check` outdated a non-error status 1 (#14167)
In the case of `uv sync` all we really need to do is handle the
`OutdatedEnvironment` error (precisely the error we yield only on
dry-runs when everything Works but we determine things are outdated) in
`OperationDiagnostic::report` (the post-processor on all
`operations::install` calls) because any diagnostic handled by that gets
downgraded to from status 2 to status 1 (although I don't know if that's
really intentional or a random other bug in our status handling... but I
figured it's best to highlight that other potential status code
incongruence than not rely on it 😄).
Fixes #12603
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Co-authored-by: John Mumm <jtfmumm@gmail.com>
