Represent DevicePolicyRefreshRate's default as a int, not a string

Change-Id: Ib34e24737947cc812c69e64d8ff4eb7a2d8775e5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2518832Reviewed-by: Owen Min <zmin@chromium.org>
Commit-Queue: Chris Sharp <csharp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#824024}

components/policy/resources/policy_templates.json

@@ -7719,7 +7719,7 @@
         'dynamic_refresh': True,
       },
       'example_value': 3600000,
-      'default': 3 * 60 * 60 * 1000,
+      'default': 10800000,
       'id': 90,
       'caption': '''Refresh rate for Device Policy''',
       'tags': [],