Bump org.junit.jupiter:junit-jupiter in /examples/ledger-api

Bumps [org.junit.jupiter:junit-jupiter](https://github.com/junit-team/junit-framework) from 5.13.1 to 5.13.4.
- [Release notes](https://github.com/junit-team/junit-framework/releases)
- [Commits](junit-team/junit-framework@r5.13.1...r5.13.4)

---
updated-dependencies:
- dependency-name: org.junit.jupiter:junit-jupiter
  dependency-version: 5.13.4
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

examples/ledger-api/build.gradle

@@ -15,7 +15,7 @@ repositories {
 dependencies {
     implementation 'org.hyperledger.fabric-chaincode-java:fabric-chaincode-shim:2.5.6'
     implementation 'org.json:json:20250517'
-    testImplementation 'org.junit.jupiter:junit-jupiter:5.13.1'
+    testImplementation 'org.junit.jupiter:junit-jupiter:5.13.4'
     testImplementation 'org.assertj:assertj-core:3.27.3'
     testImplementation 'org.mockito:mockito-core:5.18.0'
 }