Replace `any()` with `anyList()` in Mockito tests for stronger type safety (#3583)

# Description of Changes

Please provide a summary of the changes, including:

- **What was changed**  
- Updated static imports in `CheckProgramInstallTest.java` and
`PDFToFileTest.java` from `ArgumentMatchers.any` to
`ArgumentMatchers.anyList`.
- Changed all calls to `runCommandWithOutputHandling(any(List.class))`
to `runCommandWithOutputHandling(anyList())`.
- Removed unused `import java.util.List;` statements where no longer
needed.

- **Why the change was made**  
- `anyList()` provides stronger type safety than the raw `any()`,
avoiding unchecked warnings and making intent clearer when matching
`List` arguments in Mockito.
- Cleaning up unused imports keeps the test codebase tidy and free of
clutter.

---

## Checklist

### General

- [x] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [x] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md)
(if applicable)
- [x] I have performed a self-review of my own code
- [x] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md#6-testing)
for more details.