Make java.import.gradle.user.home machine-overridable.

Signed-off-by: Roland Grunberg <rgrunber@redhat.com>

Author: rgrunber

package.json

@@ -728,7 +728,7 @@
           "type": "string",
           "default": null,
           "description": "Setting for GRADLE_USER_HOME.",
-          "scope": "window",
+          "scope": "machine-overridable",
           "order": 55
         },
         "java.import.gradle.offline.enabled": {