Fix AnityaDistribution version detection with set_version service

[Sahitya0805]

Hi friends,

This PR fixes an issue where AnityaDistribution reports an incorrect package version when the set_version service is used in buildtime mode.

In such cases, the version defined in the .spec file remains unchanged, while the actual version is updated dynamically by the _service during build time. As a result, the detected version was not reflecting the effective version produced by the service.

Fix

This change updates the version detection logic to prefer the version from _service-generated sourceinfo entries (identified via _service: filenames), and falls back to the default sourceinfo when not present.

Why this approach

• Keeps the change minimal and focused
• Uses already available backend data without additional API complexity

Result

The detected version now correctly reflects the version modified by the set_version service.

Fixes: #18610

Thanks!

[eduardoj]

This PR includes a commit "Fix crash when creating an existing patchinfo package issue" not related to fixing the issue...

[Sahitya0805]

Thanks for pointing that out!

You’re right — the patchinfo fix addresses a different issue.
I’ll remove it from this PR so it only contains the AnityaDistribution fix

[hennevogel]

@Sahitya0805 https://github.com/openSUSE/open-build-service/blob/master/CONTRIBUTING.md#small-commits--pull-request-scope

[Sahitya0805]

Thanks for the clarification! I've removed the test and kept the PR focused on the fix.