Anti-flipping safeguard for vulnerability management policies

Summary

When a vulnerability appears in scan results inconsistently, it can continually transition between detected and resolved states. This can cause these problems:

1. Unclear vulnerability status
2. Continual growth of notes and vulnerability_state_transitions records, which will eventually cause performance and storage problems

We should implement "anti-flipping" safeguards to mitigate this problem. After a vulnerability has automatically transitioned between detected and resolved a certain number of times, we should flag that vulnerability as problematic (when I worked at WhiteHat Security, such vulnerabilities were called "flappers"). If a vulnerability has been flagged as problematic then it should be ignored by any further automatic status changes, and should be marked by an indicator in the UI. This will allow someone to manually review, set the correct status, and correct the projects pipeline configuration if necessary.