Display files from referenced crossref in entry table (Toro520 version)

[Toro520]

Resolves #7731 Improves code quality of - and is based on - PR #9717

Refactor getResolvedFieldOrAlias for clarity and modern style

• Use Stream API for better readability and concise code.
• Simplify the logic to fetch the first resolved field or alias.
• No change in the method's functionality or output.

Mandatory checks

• [ ] Change in CHANGELOG.md described in a way that is understandable for the average user (if applicable)
• [ ] Tests created for changes (if applicable)
• [ ] Manually tested changed features in running JabRef (always required)
• [ ] Screenshots added in PR description (for UI changes)
• [x] Checked developer's documentation: Is the information available and up to date? If not, I outlined it in this pull request.
• [ ] Checked documentation: Is the information available and up to date? If not, I created an issue at https://github.com/JabRef/user-documentation/issues or, even better, I submitted a pull request to the documentation repository.