build: add 'synchronize' type to PR validation workflow (W-23251216)

[jfeingold35]

@W-23251216@

What does this PR do?

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Acceptance Criteria

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Testing Notes

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Checklist

• This change has been approved by the CLI Review Board or approval isn't required. Anything that adds/changes/deletes commands, flags, output, or json output has to be reviewed.
• Does this follow the deprecation policy?

What issues does this PR fix or reference?

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