NVD mirror fails with: Unexpected response code: 404

### Current Behavior

I did a fresh installation from scratch and haven't configured any projects or uploaded any SBOMs yet. I installed version 5.0.5 and noticed that the vulnerability database didn't seem to have downloaded completely. There are around 180,000 vulnerabilities, but some years have a reasonable number and others only have 1 or 2 vulnerabilities.

2015: 2 CVEs
2019: 1 CVE
2021: 1 CVE
2022: 1 CVE
2023: 18 CVEs
2024: 39227 CVEs
2026: 1069 CVEs

In the NVD tab, the mirroring seemed to have been successful; it showed something like "Last mirrored 1 hour ago." Today I updated to version 5.1.0 and started a manual mirroring. In the logs, after 6 attempts, I see the following:

But the same URL that fails (https://nvd.nist.gov/feeds/json/cve/2.0/nvdcve-2.0-2026.json.gz) returns HTTP 200 from both host and container.

Now, in version 5.1.0, on the frontend NVD page I see "Last mirror failed 1h ago".

### Steps to Reproduce

1. Perform a fresh installation of v5.0.5.
2. Upgrade to v5.1.0
3. Run "Mirror now" for NVD.

### Expected Behavior

I understand that there shouldn't be years with only 1 or 2 vulnerabilities.

### Dependency-Track Version

5.x

### Browser

Google Chrome

### 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 defect was already reported

Start from the NVD tab's "Mirror now" flow and inspect the logging and response handling for the failing nvdcve-2.0-2026.json.gz URL. Reproduce the upgrade from 5.0.5 to 5.1.0 and compare the application request with the successful host and container requests; done means mirroring completes without the false 404 and the NVD page no longer reports a failed mirror.

Written by the indexing model from the issue text.