Follow-up from "Populate missing dismissal information for vulnerabilities"

The following discussion from !46370 (merged) should be addressed:

• @pbair started a discussion:

  Can we create a follow-up issue to remove this temporary index?

Description

As part of !46370 (merged), we've introduced a new index to speed up the process of scheduling background jobs. This index should be removed to prevent having "write amplification" issues.

Implementation plan

• backend database Create a new database migration to remove the index named temporary_index_vulnerabilities_on_id from the vulnerabilities table.