This merge request includes follow-up changes for creating a model for instance-level event filters. It adds a new method called `allowed_to_stream?` to check if an external audit event destination is allowed to stream a specific audit operation. It also includes some refactoring and code cleanup.
What does this MR do and why?
Migration and model for
InstanceEventTypeFilter which represents audit event type filters for instance level external audit event destinations were added in !123330 (merged). This is a follow up MR to that and adds additional code changes around the models in this MR in relation to the external destinations.
MR acceptance checklist
This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.
I have evaluated the MR acceptance checklist for this MR.
Related to #416450 (closed)