Switch from XContentType to MediaType to fix compilation errors (opensearch-project#232)

Signed-off-by: Martin Gaievski <[email protected]>

Author: martin-gaievski

src/test/java/org/opensearch/neuralsearch/OpenSearchSecureRestTestCase.java

@@ -31,6 +31,7 @@
 import org.opensearch.common.util.concurrent.ThreadContext;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.xcontent.DeprecationHandler;
+import org.opensearch.core.xcontent.MediaType;
 import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.test.rest.OpenSearchRestTestCase;
@@ -131,7 +132,7 @@ protected boolean preserveIndicesUponCompletion() {
     @After
     public void deleteExternalIndices() throws IOException {
         final Response response = client().performRequest(new Request("GET", "/_cat/indices?format=json" + "&expand_wildcards=all"));
-        final XContentType xContentType = XContentType.fromMediaType(response.getEntity().getContentType().getValue());
+        final MediaType xContentType = MediaType.fromMediaType(String.valueOf(response.getEntity().getContentType()));
         try (
             final XContentParser parser = xContentType.xContent()
                 .createParser(