Add spatial reference inside geometry in EsriFormat

As mentioned on issue 6992, EsriFormat was adding the spatial reference
outside the geometry, failing to insert data via the Arcgis rest API.
The spatial reference should be inside the geometry.

src/ol/format/esrijson.js

@@ -623,6 +623,12 @@ ol.format.EsriJSON.prototype.writeFeatureObject = function(
   if (geometry) {
     object['geometry'] =
       ol.format.EsriJSON.writeGeometry_(geometry, opt_options);
+    if (opt_options && opt_options.featureProjection) {
+      object['geometry']['spatialReference'] = /** @type {EsriJSONCRS} */({
+        wkid: ol.proj.get(
+            opt_options.featureProjection).getCode().split(':').pop()
+      });
+    }
   }
   var properties = feature.getProperties();
   delete properties[feature.getGeometryName()];
@@ -631,12 +637,6 @@ ol.format.EsriJSON.prototype.writeFeatureObject = function(
   } else {
     object['attributes'] = {};
   }
-  if (opt_options && opt_options.featureProjection) {
-    object['spatialReference'] = /** @type {EsriJSONCRS} */({
-      wkid: ol.proj.get(
-          opt_options.featureProjection).getCode().split(':').pop()
-    });
-  }
   return object;
 };