GitHubAdvisoryMirrorTaskTest fails due to not accounting for local time vs UTC

### Current Behavior

When running tests:
```
[ERROR] Tests run: 17, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 8.000 s <<< FAILURE! -- in org.dependencytrack.tasks.GitHubAdvisoryMirrorTaskTest
[ERROR] org.dependencytrack.tasks.GitHubAdvisoryMirrorTaskTest.testProcessAdvisory -- Time elapsed: 0.234 s <<< FAILURE!
java.lang.AssertionError:

Expecting actual:
2022-03-11T16:00:00.000 (org.datanucleus.store.types.wrappers.Date)
to have same year, month and day as:
2022-03-12T00:00:00.000 (java.util.Date)
but had not.
at org.dependencytrack.tasks.GitHubAdvisoryMirrorTaskTest.testProcessAdvisory(GitHubAdvisoryMirrorTaskTest.java:129)
```

This appears to be a UTC vs Local time difference.

I think the issue is when we do this:
```
if (StringUtils.isNotBlank(publishedDateString)) {
vulnerability.setPublished(Date.from(OffsetDateTime.parse(publishedDateString).toInstant()));
}
```
we land on midnight UTC...which then becomes the previous day when adjusted for my local time (-8).

One option might be to trim off the time:
```
if (StringUtils.isNotBlank(publishedDateString)) {
OffsetDateTime odt = OffsetDateTime.parse(publishedDateString);
LocalDate localDate = odt.toLocalDate();
vulnerability.setPublished(java.sql.Date.valueOf(localDate));
}
```

### Steps to Reproduce

1. Live in a TZ behind UTC.
2. Run tests.

### Expected Behavior

Test either accounts for timezone or we drop the time component.

### Dependency-Track Version

4.13.x

### Dependency-Track Distribution

Container Image

### Database Server

N/A

### Database Server Version

_No response_

### Browser

N/A

### 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 defect was already reported