Add support for custom Jira required fields

### Current Behavior

Currently, it is impossible for dtrack to create tickets in Jira projects that have custom fields marked as required.

When configuring such a queue, we get this error:
```
WARN [JiraPublisher] Destination responded with with status code 400, likely indicating a processing failure (PublishContext{notificationGroup=NEW_VULNERABLE_DEPENDENCY, notificationLevel=INFORMATIONAL, notificationScope=PORTFOLIO, notificationTimestamp=2026-01-22T09:01:36.43763814Z, notificationSubjects={component=Component[uuid=94f87321-a5d1-4c2f-b2fe-95165debebc6, group=null, name=componentName, version=componentVersion], project=Project[uuid=c9c9539a-e381-4b36-ac52-6a7ab83b2c95, name=projectName, version=projectVersion], vulnerabilities=[Vulnerability[id=INT-001, source=INTERNAL]]}}) [principal=xxx, requestUri=/v1/notification/publisher/test/{uuid}, requestId=651023c8-f1ef-4caf-91cd-9f68a530b8a2, requestMethod=POST]
```

### Proposed Behavior

This would require dtrack to connect to Jira during the alert setup to request the configured project's fields information.

Let us know if this is something you're interested in adding!

### Checklist

- [x] I have read and understand the [contributing guidelines](https://github.com/DependencyTrack/dependency-track/blob/master/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