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/java/stirling/software/SPDF/model/api/security/SanitizePdfRequest.java

@@ -17,9 +17,12 @@ public class SanitizePdfRequest extends PDFFile {
     @Schema(description = "Remove embedded files from the PDF", defaultValue = "false")
     private boolean removeEmbeddedFiles;
 
-    @Schema(description = "Remove metadata from the PDF", defaultValue = "false")
-    private boolean removeMetadata;
+    @Schema(description = "Remove XMP metadata from the PDF", defaultValue = "false")
+    private boolean removeXMPMetadata;
 
+    @Schema(description = "Remove document info metadata from the PDF", defaultValue = "false")
+    private boolean removeMetadata;
+    
     @Schema(description = "Remove links from the PDF", defaultValue = "false")
     private boolean removeLinks;