This fixes a failing unit test on macOS.


`ApplicationPropertiesLogicTest.tempFileManagement_defaults_and_overrides()`
has 4 asserts that will fail with this error on macOS:

```
org.opentest4j.AssertionFailedError: expected: </var/folders/6d/12xt4b4m8xjf3t0059_w18bh0000gn/T/stirling-pdf> but was: </var/folders/6d/12xt4b4m8xjf3t0059_w18bh0000gn/T//stirling-pdf>
	at app//org.junit.jupiter.api.AssertionFailureBuilder.build(AssertionFailureBuilder.java:151)
	at app//org.junit.jupiter.api.AssertionFailureBuilder.buildAndThrow(AssertionFailureBuilder.java:132)
	at app//org.junit.jupiter.api.AssertEquals.failNotEqual(AssertEquals.java:197)
	at app//org.junit.jupiter.api.AssertEquals.assertEquals(AssertEquals.java:182)
	at app//org.junit.jupiter.api.AssertEquals.assertEquals(AssertEquals.java:177)
	at app//org.junit.jupiter.api.Assertions.assertEquals(Assertions.java:1145)
	at app//stirling.software.common.model.ApplicationPropertiesLogicTest.tempFileManagement_defaults_and_overrides(ApplicationPropertiesLogicTest.java:40)
	at java.base@24.0.2/java.lang.reflect.Method.invoke(Method.java:565)
	at java.base@24.0.2/java.util.ArrayList.forEach(ArrayList.java:1604)
	at java.base@24.0.2/java.util.ArrayList.forEach(ArrayList.java:1604)
```

Note the double `/` in the actual path here: `/T//stirling-pdf`.

# Description of Changes

The fix creates a lambda:

```
Function<String, String> normalize = s ->Paths.get(s).normalize().toString();
```
and applies it in all 4 broken tests.

## 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/devGuide/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)
- [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/devGuide/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)

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