Automatic suppresions for vulnerability aliases

### Current Behavior

Currently, when I suppress a vulnerability/apply a VEX file in a project in DT v5, the suppression is not applied also for aliases of that vulnerability. For example, if suppression is applied to a vulnerability identified by a CVE number, but the vulnerability also have a GitHub identifier, the later one is not suppressed as well.

### Proposed Behavior

When I suppress a vulnerability, I expect also the aliases to be suppressed automatically.

### 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

Start by tracing how vulnerability suppressions and VEX files are applied in Dependency-Track, then inspect how vulnerability aliases are represented and resolved. Add coverage for a vulnerability identified by one identifier with an additional GitHub alias, and verify that suppressing the vulnerability also suppresses its aliases.

Written by the indexing model from the issue text.