Resolve "Resolve cross DB issues in ee/app/services/vulnerabilities/bulk_dismiss_service.rb"

What does this MR do and why?

This MR resolves cross-DB transactions when updating vulnerability tables together with notes table in the same transaction
The notes table update was moved to after the transaction so that the il be a separate transaction
A follow-up issue has been opened to create a worker to update the notes table, to minimise the changes it the notes table will not be updated due to failures

MR acceptance checklist

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Related to #486990 (closed)