Remove code remnants from semantic_text previous iterations in featur…

…e branch (elastic#107508)

Removes changes for code already removed from the `semantic_text`
feature branch.

This is prep work for opening up `semantic_text` PRs in order to remove
irrelevant changes.

server/src/main/java/org/elasticsearch/common/xcontent/support/XContentMapValues.java

@@ -555,7 +555,7 @@ public static Map<String, Object> nodeMapValue(Object node, String desc) {
         if (node instanceof Map) {
             return (Map<String, Object>) node;
         } else {
-            throw new ElasticsearchParseException(desc + " should be a hash but was of type: " + node.getClass());
+            throw new ElasticsearchParseException(desc + " should be a map but was of type: " + node.getClass());
         }
     }
 

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/MachineLearning.java

@@ -49,7 +49,6 @@
 import org.elasticsearch.features.NodeFeature;
 import org.elasticsearch.index.analysis.CharFilterFactory;
 import org.elasticsearch.index.analysis.TokenizerFactory;
-import org.elasticsearch.index.mapper.Mapper;
 import org.elasticsearch.index.query.QueryBuilder;
 import org.elasticsearch.indices.AssociatedIndexDescriptor;
 import org.elasticsearch.indices.SystemIndexDescriptor;
@@ -69,7 +68,6 @@
 import org.elasticsearch.plugins.CircuitBreakerPlugin;
 import org.elasticsearch.plugins.ExtensiblePlugin;
 import org.elasticsearch.plugins.IngestPlugin;
-import org.elasticsearch.plugins.MapperPlugin;
 import org.elasticsearch.plugins.PersistentTaskPlugin;
 import org.elasticsearch.plugins.Platforms;
 import org.elasticsearch.plugins.Plugin;
@@ -365,7 +363,6 @@
 import org.elasticsearch.xpack.ml.job.process.normalizer.NormalizerProcessFactory;
 import org.elasticsearch.xpack.ml.job.snapshot.upgrader.SnapshotUpgradeTaskExecutor;
 import org.elasticsearch.xpack.ml.job.task.OpenJobPersistentTasksExecutor;
-import org.elasticsearch.xpack.ml.mapper.SemanticTextFieldMapper;
 import org.elasticsearch.xpack.ml.notifications.AnomalyDetectionAuditor;
 import org.elasticsearch.xpack.ml.notifications.DataFrameAnalyticsAuditor;
 import org.elasticsearch.xpack.ml.notifications.InferenceAuditor;
@@ -485,8 +482,7 @@ public class MachineLearning extends Plugin
         PersistentTaskPlugin,
         SearchPlugin,
         ShutdownAwarePlugin,
-        ExtensiblePlugin,
-        MapperPlugin {
+        ExtensiblePlugin {
     public static final String NAME = "ml";
     public static final String BASE_PATH = "/_ml/";
     // Endpoints that were deprecated in 7.x can still be called in 8.x using the REST compatibility layer
@@ -2308,12 +2304,4 @@ public void signalShutdown(Collection<String> shutdownNodeIds) {
             mlLifeCycleService.get().signalGracefulShutdown(shutdownNodeIds);
         }
     }
-
-    @Override
-    public Map<String, Mapper.TypeParser> getMappers() {
-        if (SemanticTextFeature.isEnabled()) {
-            return Map.of(SemanticTextFieldMapper.CONTENT_TYPE, SemanticTextFieldMapper.PARSER);
-        }
-        return Map.of();
-    }
 }