Fix the version check for LegacyGeoShapeFieldMapper (#38547)

Change version check from 7.0 to 6.6 in BaseGeoShapeFieldMapper to correctly use LegacyGeoShapeFieldMapper for indexes created prior to 6.6.

Author: nknize

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

@@ -190,7 +190,7 @@ public Mapper.Builder parse(String name, Map<String, Object> node, ParserContext
                 }
             }
             final Builder builder;
-            if (parsedDeprecatedParams || parserContext.indexVersionCreated().before(Version.V_7_0_0)) {
+            if (parsedDeprecatedParams || parserContext.indexVersionCreated().before(Version.V_6_6_0)) {
                 // Legacy index-based shape
                 builder = new LegacyGeoShapeFieldMapper.Builder(name, deprecatedParameters);
             } else {

server/src/test/java/org/elasticsearch/index/mapper/ExternalMapper.java

@@ -87,7 +87,7 @@ public ExternalMapper build(BuilderContext context) {
             BinaryFieldMapper binMapper = binBuilder.build(context);
             BooleanFieldMapper boolMapper = boolBuilder.build(context);
             GeoPointFieldMapper pointMapper = latLonPointBuilder.build(context);
-            BaseGeoShapeFieldMapper shapeMapper = (context.indexCreatedVersion().before(Version.V_7_0_0))
+            BaseGeoShapeFieldMapper shapeMapper = (context.indexCreatedVersion().before(Version.V_6_6_0))
                 ? legacyShapeBuilder.build(context)
                 : shapeBuilder.build(context);
             FieldMapper stringMapper = (FieldMapper)stringBuilder.build(context);