Notifications in the UI have a different visible name than the actual event

### Current Behavior

in DT4 these names like VEX_PROCESSED were the literal name that were received in the webhook. In DT5, these enums have prefixes, like `INFORMATIONAL` -> `LEVEL_INFORMATIONAL`, `VEX_PROCESSED` -> `GROUP_VEX_PROCESSED`.

### Steps to Reproduce

1. Create a webhook

### Expected Behavior

I expected the names to reflect the event type or have it be visible in the UI the even they correlate to.

### Dependency-Track Frontend Version

5.x

### Browser

Google Chrome

### Browser Version

n/a

### Operating System

macOS

### 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/frontend/issues) for whether this defect was already reported