Fix testIndexDeletionDuringSnapshotCreationInQueue flaky test (#11726)

* Fix testIndexDeletionDuringSnapshotCreationInQueue flaky test

Signed-off-by: Suraj Singh <surajrider@gmail.com>

* Update comment

Signed-off-by: Suraj Singh <surajrider@gmail.com>

---------

Signed-off-by: Suraj Singh <surajrider@gmail.com>

Author: dreamer-89

server/src/internalClusterTest/java/org/opensearch/snapshots/DedicatedClusterSnapshotRestoreIT.java

@@ -1457,6 +1457,13 @@ public void testIndexDeletionDuringSnapshotCreationInQueue() throws Exception {
 
         clusterAdmin().prepareRestoreSnapshot("test-repo", "test-snap").get();
         ensureGreen("test-idx");
+
+        // Wait for snapshot process to complete to prevent conflict with repository clean up
+        assertBusy(() -> {
+            SnapshotInfo snapshotInfo = getSnapshot("test-repo", "test-snap-2");
+            assertTrue(snapshotInfo.state().completed());
+            assertEquals(SnapshotState.PARTIAL, snapshotInfo.state());
+        }, 1, TimeUnit.MINUTES);
     }
 
     private long calculateTotalFilesSize(List<Path> files) {