Enable the feature flag for geo-shape decimation by default

This is the follow-up of the MR Geoshape decimation.

We enabled the feature flags in two data partitions on 12/6/2022 and shape decimation was applied to the new ingested data with geo-shapes from different users. We didn't see any problem on the shape decimation so far.

This MR is to enable the feature flag of the shape decimation for all data partitions by default. Client can still disable this feature in a given data partition through the Partition Service:

{
   "indexer-decimation-enabled": {
        "sensitive": false,
        "value": "false"
    }
}

docs/tutorial/PreviewFeatures.md

@@ -8,17 +8,18 @@ by implementing Ramer–Douglas–Peucker algorithm:
 - Polygon
 - MultiPolygon  
 
-In order to reduce the risk when extended evaluation of the solution is still on going, a feature flag that is managed by 
-the Partition Service is applied to the solution.
-Here is an example to enable this feature by setting the property "indexer-decimation-enabled" in a given data partition:
+
+The feature is enabled by default for all data partitions. If client does not want the geo-shape to be decimated in their
+data partitions, they can disable geo-shape decimation through the Partition Service.  
+Here is an example to disable this feature by setting the property "indexer-decimation-enabled" in a given data partition:
 ```
 {
    "indexer-decimation-enabled": {
         "sensitive": false,
-        "value": "true"
+        "value": "false"
     }
 }
 ```
 
-If the property "indexer-decimation-enabled" is not created or the property value is set to "false" (String type) in the 
-given data partition, the geo-shape decimation will be ignored.
+If the property "indexer-decimation-enabled" is not created or the property value is set to "true" (String type) in the 
+given data partition, the geo-shape decimation will be enabled.