Don't enable docvalues by default for the time being. (#124787)

By change index.mapping.use_doc_values_skipper setting's default to false.

Author: martijnvg

server/src/main/java/org/elasticsearch/index/IndexSettings.java

@@ -688,7 +688,7 @@ public boolean isES87TSDBCodecEnabled() {
     public static final FeatureFlag DOC_VALUES_SKIPPER = new FeatureFlag("doc_values_skipper");
     public static final Setting<Boolean> USE_DOC_VALUES_SKIPPER = Setting.boolSetting(
         "index.mapping.use_doc_values_skipper",
-        IndexSettings.DOC_VALUES_SKIPPER.isEnabled(),
+        false,
         Property.IndexScope,
         Property.Final
     );