Detect Breaking Changes check does not fail on new method added to an @…

…publicapi interface (#16585)

Signed-off-by: Andriy Redko <andriy.redko@aiven.io>
(cherry picked from commit aa5c39b)
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

server/build.gradle

@@ -450,6 +450,7 @@ tasks.register("japicmp", me.champeau.gradle.japicmp.JapicmpTask) {
     onlyModified = true
     failOnModification = true
     ignoreMissingClasses = true
+    failOnSourceIncompatibility = true
     annotationIncludes = ['@org.opensearch.common.annotation.PublicApi', '@org.opensearch.common.annotation.DeprecatedApi']
     annotationExcludes = ['@org.opensearch.common.annotation.InternalApi']
     txtOutputFile = layout.buildDirectory.file("reports/java-compatibility/report.txt")