http_client: Ensure GitHub digest prefix is always stripped (#64905)

## Summary

Fixes an inconsistency we had when deserializing responses from the
GitHub releases API.

## Testing

Added some deserialization tests that describe the intended behavior

## Self-review

- [X] I've reviewed my diff for quality, security, reliability, and
performance.
- [X] Tests cover the new or changed behavior.

Release Notes:

- N/A
ead2d9eac0Finn Evers committed on 9/29/2026, 9:20:46 AM· committed by GitHubparentbd74733
1 file changedLine totals unavailable