Add non-blocking node deletion validation to deployments

[shangyian]

Summary

When deploying node deletions, we should allow deployments to proceed even when the deleted nodes have references, but mark those specific node deployments as failed. The overall deployment status will also be failed, providing clear feedback about what couldn't be deleted and why.

Previously, deleting a node during deployment, we would not validate if there were any downstream or dimension link references to this node. If any node had references, they would be rendered invalid, but we wouldn't make this obvious to the user as a part of the deployment process, so users would discover this issue much later, with no visibility into which deletion caused what failure and why.

This change adds a validation stage after node deletion. This validation is non-blocking and involves:

1. Checking for references by querying for nodes that depend on nodes being deleted (via parent relationships or dimension links).
2. Allowing the rest of the deployment to proceed and return individual deployment results
3. Mark nodes with deleted node references as failed.
4. Fail overall deployment

Test Plan

• PR has an associated issue: #
• make check passes
• make test shows 100% unit test coverage

Deployment Plan

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