upgrade: add automatic repair for missing comment validation errors

[fqazi]

Currently, we have validation to detect missing comments inside crdb_internal.invalid_objects, but we don't have an automated repair during upgrades to fix these problems. We should extend the automatic repair to include support for cleaning up comments that exist against missing descriptors.

Jira issue: CRDB-53312

Epic CRDB-49398

[blathers-crl]

Hi @fqazi, please add branch-* labels to identify which branch(es) this C-bug affects.

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