Bump com.google.guava:guava in /samples/java-contract

Bumps [com.google.guava:guava](https://github.com/google/guava) from 33.4.6-jre to 33.4.8-jre.
- [Release notes](https://github.com/google/guava/releases)
- [Commits](https://github.com/google/guava/commits)

---
updated-dependencies:
- dependency-name: com.google.guava:guava
  dependency-version: 33.4.8-jre
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

samples/java-contract/build.gradle

@@ -25,7 +25,7 @@ dependencies {
     testImplementation 'org.junit.jupiter:junit-jupiter:5.12.2'
 
     // This dependency is used by the application.
-    implementation 'com.google.guava:guava:33.4.6-jre'
+    implementation 'com.google.guava:guava:33.4.8-jre'
 }
 
 application {