Add supported_on to Wifi Sync Enterprise Policy

Bug: 1117619
Change-Id: I1ce7cbfdd8da85fff0a584bd2f8254075ea305f4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2628209Reviewed-by: Jon Mann <jonmann@chromium.org>
Reviewed-by: Pavol Marko <pmarko@chromium.org>
Commit-Queue: Claude van der Merwe <cvandermerwe@google.com>
Cr-Commit-Position: refs/heads/master@{#843670}

components/policy/resources/policy_templates.json

@@ -16616,7 +16616,7 @@
       'owners': ['jonmann@chromium.org', 'cvandermerwe@google.com'],
       'type': 'main',
       'schema': { 'type': 'boolean' },
-      'future_on': ['chrome_os'],
+      'supported_on': ['chrome_os:89-'],
       'features': {
         'dynamic_refresh': True,
         'per_profile': True,