Configure test-retry plugin filter properly (#8933) (#8939)

The intent of #8825 was to retry only specified tests. The wrong
parameter was configured though: ['filter' should be set][1], not
'classRetry'.

[1]: https://github.com/gradle/test-retry-gradle-plugin/blob/main/README.adoc#filtering


(cherry picked from commit 5495c64)

Signed-off-by: Andrew Ross <andrross@amazon.com>
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

build.gradle

@@ -459,7 +459,7 @@ subprojects {
         maxFailures = 10
       }
       failOnPassedAfterRetry = false
-      classRetry {
+      filter {
         includeClasses.add("org.opensearch.action.admin.cluster.node.tasks.ResourceAwareTasksTests")
         includeClasses.add("org.opensearch.action.admin.cluster.tasks.PendingTasksBlocksIT")
         includeClasses.add("org.opensearch.action.admin.indices.create.CreateIndexIT")