checks the compatibility of the licenses (#2844)

# Description of Changes

### What was changed
- An **automated license check** was integrated into the CI/CD workflow
(`build.yml` and `licenses-update.yml`).
- A new file, `allowed-licenses.json`, was added to explicitly define
the permitted licenses.
- The **Gradle build process** was updated to run `checkLicense` and
detect any non-compliant licenses.

### Why the change was made
- **Improved license compliance** to ensure only compatible licenses are
used.
- **Automated license validation** within the CI/CD workflow to detect
potential incompatibilities early.
- **Legal risk mitigation** by excluding problematic licenses like
**GPL-2.0 (without Classpath Exception)**.

### Any challenges encountered
- The **allowed license list had to be manually curated** to ensure all
relevant open-source libraries were covered.
- Some dependencies use **slightly different license names** (e.g.,
`"Apache License, Version 2.0"` vs. `"Apache-2.0"`), which needed to be
handled in the validation process.

---

## 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)
- [x] 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

- [x] 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)

- [x] 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.

build.gradle

@@ -41,6 +41,7 @@ repositories {
 
 licenseReport {
     renderers = [new JsonReportRenderer()]
+    allowedLicensesFile = new File("$projectDir/allowed-licenses.json")
 }
 
 sourceSets {
@@ -366,7 +367,7 @@ dependencies {
         exclude group: "commons-logging", module: "commons-logging"
     }
     implementation "org.apache.pdfbox:preflight:$pdfboxVersion"
-    
+
 
     implementation ("org.apache.pdfbox:xmpbox:$pdfboxVersion") {
         exclude group: "commons-logging", module: "commons-logging"