Add notifications for comments posted on vulnerability analyses

### Current Behavior

Currently, no notifications (at least no webhook notifications) are sent when a comment is posted on a vulnerability analysis. Notifications are only sent when the state is changed or the vulnerability is suppressed.

### Proposed Behavior

I want to be able to configure notifications for comments on detected vulnerabilities. I would like to have a custom notification group for this, for example `VULNERABILITY_ANALYSIS_COMMENT`, that I can enable for an alert. The notification should include the comment, timestamp and who posted the comment.

I would like to have this behaviour so that I can stay up to date on when other users comment on found vulnerabilities and keep the discussion going if needed. This issue might be slightly related to https://github.com/DependencyTrack/dependency-track/issues/4744, but I believe the enhancement I'm requesting is separate from https://github.com/DependencyTrack/dependency-track/issues/4744.

### Checklist

- [x] I have read and understand the [contributing guidelines](https://github.com/DependencyTrack/dependency-track/blob/main/CONTRIBUTING.md#filing-issues)
- [x] I have checked the [existing issues](https://github.com/DependencyTrack/dependency-track/issues) for whether this enhancement was already requested

No implementation files or tests are named. Start by tracing the existing notifications for vulnerability state changes and suppressions, and review related issue #4744 to understand the boundary. Done means comments on vulnerability analyses can trigger a configurable notification group containing the comment, timestamp, and author.

Written by the indexing model from the issue text.