Update a test to match new indexResponse.aliases() type.

Signed-off-by: MaxKsyunz <[email protected]>

Author: MaxKsyunz

opensearch/src/test/java/org/opensearch/sql/opensearch/client/OpenSearchNodeClientTest.java

@@ -371,9 +371,7 @@ void cleanupWithoutScrollId() {
   @Test
   void getIndices() {
     AliasMetadata aliasMetadata = mock(AliasMetadata.class);
-    ImmutableOpenMap.Builder<String, List<AliasMetadata>> builder = ImmutableOpenMap.builder();
-    builder.fPut("index",Arrays.asList(aliasMetadata));
-    final ImmutableOpenMap<String, List<AliasMetadata>> openMap = builder.build();
+    final var openMap = Map.of("index", List.of(aliasMetadata));
     when(aliasMetadata.alias()).thenReturn("index_alias");
     when(nodeClient.admin().indices()
         .prepareGetIndex()