Remove future flag from UserNativePrintersAllowed policy

The feature has been released.

Bug: 1011028
Change-Id: Iec435ca812e4a6a6aa13336acd70fc348a03c66b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1863295
Commit-Queue: Vladislav Kuzkokov <vkuzkokov@chromium.org>
Commit-Queue: Sergey Poromov <poromov@chromium.org>
Reviewed-by: Sergey Poromov <poromov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#706068}

components/policy/resources/policy_templates.json

@@ -15110,7 +15110,6 @@
       ],
       'supported_on': ['chrome_os:68-'],
       'device_only': True,
-      'future': True,
       'features': {
         'dynamic_refresh': True,
       },