Sanataize PDF improvements (#3251)

# Description of Changes

Please provide a summary of the changes, including:

- Make distinction between metadata removal and XMP metadata removal
- Change file loaders to only edit metadata for certain ops

Closes #(issue_number)

---

## 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/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/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.

src/main/resources/templates/security/sanitize-pdf.html

@@ -29,8 +29,12 @@
                   <label for="removeEmbeddedFiles" th:text="#{sanitizePDF.selectText.2}"></label>
                 </div>
                 <div class="form-check ms-3">
-                  <input type="checkbox" id="removeMetadata" name="removeMetadata" checked>
-                  <label for="removeMetadata" th:text="#{sanitizePDF.selectText.3}"></label>
+                  <input type="checkbox" id="removeXMPMetadata" name="removeXMPMetadata">
+                  <label for="removeXMPMetadata" th:text="#{sanitizePDF.selectText.3}"></label>
+                </div>
+                <div class="form-check ms-3">
+                  <input type="checkbox" id="removeMetadata" name="removeMetadata">
+                  <label for="removeMetadata" th:text="#{sanitizePDF.selectText.6}"></label>
                 </div>
                 <div class="form-check ms-3">
                   <input type="checkbox" id="removeLinks" name="removeLinks">