Include common in Spotless formatting (#3605)

# Description of Changes

Please provide a summary of the changes, including:

- What was changed
- Why the change was made
- Any challenges encountered

Closes #(issue_number)

---

## 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)
- [ ] 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

- [ ] 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.

build.gradle

@@ -1,6 +1,6 @@
 plugins {
     id "java"
-    id 'jacoco'
+    id "jacoco"
     id "org.springframework.boot" version "3.5.0"
     id "io.spring.dependency-management" version "1.1.7"
     id "org.springdoc.openapi-gradle-plugin" version "1.9.0"
@@ -374,7 +374,8 @@ launch4j {
 
 spotless {
     java {
-        target project.fileTree('src').include('**/*.java')
+        target sourceSets.main.allJava
+        target project(':common').sourceSets.main.allJava
 
         googleJavaFormat("1.27.0").aosp().reorderImports(false)
 
@@ -543,7 +544,7 @@ dependencies {
     compileOnly "org.projectlombok:lombok:$lombokVersion"
     annotationProcessor "org.projectlombok:lombok:$lombokVersion"
 
-  // Mockito (core)
+    // Mockito (core)
     testImplementation 'org.mockito:mockito-core:5.18.0'
     testRuntimeOnly 'org.mockito:mockito-inline:5.2.0'
 }