sklearn: enable gamma release for 1.4-2-py312 (#6376)

Author: jinyan-li1

.github/config/image/sklearn/sagemaker-1.4-2-py312.yml

@@ -28,7 +28,7 @@ build:
   sklearn_container_branch: "master"
 
 release:
-  release: false
+  release: true
   force_release: false
   public_registry: false
   private_registry: true