fix(common): Bump assertj-core from 3.9.1 to 3.27.7 (opensearch-project#5294)

Addresses CVE-2026-24400 (GHSA-rqfh-9r24-8c9r), an XXE vulnerability
in AssertJ's isXmlEqualTo assertion when parsing untrusted XML. While
the vulnerable method is not used in this codebase and assertj-core is
test-scoped only, this bump resolves the security scanner finding on
the 2.19 branch.

Signed-off-by: Chen Dai <daichen@amazon.com>

Author: dai-chen

common/build.gradle

@@ -45,7 +45,7 @@ dependencies {
     implementation "com.github.seancfoley:ipaddress:5.4.2"
 
     testImplementation group: 'junit', name: 'junit', version: '4.13.2'
-    testImplementation group: 'org.assertj', name: 'assertj-core', version: '3.9.1'
+    testImplementation group: 'org.assertj', name: 'assertj-core', version: '3.27.7'
     testImplementation group: 'com.google.guava', name: 'guava', version: "${guava_version}"
     testImplementation group: 'org.hamcrest', name: 'hamcrest-library', version: '2.1'
     testImplementation('org.junit.jupiter:junit-jupiter:5.9.3')