Add landscape page size options (#6248)

# Description of Changes

Adds orientation (portrait/landscape) to the Adjust Page Scale tool.

- Orientation as a separate parameter (per review), sent through to the
backend
- ScalePagesController simplified; PDFWithPageSize gains the orientation
field
- Regenerated tool_models.py; frontend + backend tests added

---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] 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/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] 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/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### Translations (if applicable)

- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### 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 run `task check` to verify linters, typechecks, and tests
pass
- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md#7-testing)
for more details.

---------

Co-authored-by: ConnorYoh <[email protected]>

app/core/src/test/java/stirling/software/SPDF/controller/api/ScalePagesControllerTest.java

@@ -237,7 +237,8 @@ class ScalePagesControllerTest {
 
         ScalePagesRequest request = new ScalePagesRequest();
         request.setFileInput(file);
-        request.setPageSize("A4_LANDSCAPE");
+        request.setPageSize("A4");
+        request.setOrientation("LANDSCAPE");
         request.setScaleFactor(1.0f);
 
         setupFactory();