Text field dynamic field tweak (elastic#129332)

Pass down actual index version when creating text field mapper builder when mapping dynamic field.

Otherwise, bwc logic always has the wrong index version in mixed cluster scenario and dynamic mapping occurs.

Author: martijnvg

server/src/main/java/org/elasticsearch/index/mapper/DynamicFieldsBuilder.java

@@ -334,11 +334,17 @@ public boolean newDynamicStringField(DocumentParserContext context, String name)
                     mapperBuilderContext
                 );
             } else {
+                var indexSettings = context.indexSettings();
                 return createDynamicField(
-                    new TextFieldMapper.Builder(name, context.indexAnalyzers(), SourceFieldMapper.isSynthetic(context.indexSettings()))
-                        .addMultiField(
-                            new KeywordFieldMapper.Builder("keyword", context.indexSettings().getIndexVersionCreated()).ignoreAbove(256)
-                        ),
+                    new TextFieldMapper.Builder(
+                        name,
+                        indexSettings.getIndexVersionCreated(),
+                        context.indexAnalyzers(),
+                        SourceFieldMapper.isSynthetic(indexSettings),
+                        false
+                    ).addMultiField(
+                        new KeywordFieldMapper.Builder("keyword", context.indexSettings().getIndexVersionCreated()).ignoreAbove(256)
+                    ),
                     context
                 );
             }