Disable action items for dismissed vulnerabilities

When a vulnerability is dismissed, users can still create an issue for it.

We should disable this option, since dismissed vulnerabilities should not be of interest anymore.

User information

For: Persona: Software developer Persona: Security Analyst

Story: As someone who manages vulnerabilities, I want to know their status and if action is needed to remediate them, so that I can focus on the most severe / highest priority vulnerabilities in my project(s).

If an issue can be opened from a dismissed/whitelisted vulnerability then 1) this causes confusion as to why the vulnerability was dismissed in the first place and 2) causes workflow issues since whitelisted vulns should act like closed issues.