add preset xContentRegistry to ingestProcessors for custom parametize…

…d local models

Curently local models that use the parameters map within the payload to create a request can not create objects to be used for local model prediction. This requires a opensearch core change because it needs the contentRegistry,however given there is not much dependency on the registry (currently) we can give it the preset registry given in the MachineLearningPlugin class vai the getNamedXContent() class

Signed-off-by: Brian Flores <iflorbri@amazon.com>

plugin/src/main/java/org/opensearch/ml/plugin/MachineLearningPlugin.java

@@ -1062,10 +1062,12 @@ public void loadExtensions(ExtensionLoader loader) {
     @Override
     public Map<String, org.opensearch.ingest.Processor.Factory> getProcessors(org.opensearch.ingest.Processor.Parameters parameters) {
         Map<String, org.opensearch.ingest.Processor.Factory> processors = new HashMap<>();
+        NamedXContentRegistry contentRegistry = new NamedXContentRegistry(getNamedXContent());
+
         processors
             .put(
                 MLInferenceIngestProcessor.TYPE,
-                new MLInferenceIngestProcessor.Factory(parameters.scriptService, parameters.client, xContentRegistry)
+                new MLInferenceIngestProcessor.Factory(parameters.scriptService, parameters.client, contentRegistry)
             );
         return Collections.unmodifiableMap(processors);
     }