Add desired sharding_key to sbom_occurrences_vulnerabilities

What does this MR do and why?

This MR:

• sets classes for sbom_occurrences_vulnerabilities table that was previously missing. The missing class is the reason why the automation runs were not able to pick up this table until now.
• and once the class is set, the automation keep in !139747 (diffs) is able to pick up this table and set a desired sharding key for this table.

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Related to #432900 (closed)