Add default values for Default*GuardSetting

Bug: 1139046
Change-Id: Ib3cb0164c2003b69e8b70c07fb427de5a0a35f40
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2512292Reviewed-by: Owen Min <zmin@chromium.org>
Commit-Queue: Chris Sharp <csharp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#823337}

components/policy/resources/policy_templates.json

@@ -5716,6 +5716,7 @@
         'per_profile': True,
       },
       'example_value': 2,
+      'default': None,
       'id': 320,
       'caption': '''Control use of the Web Bluetooth API''',
       'tags': ['website-sharing'],
@@ -5816,6 +5817,7 @@
         'per_profile': True,
       },
       'example_value': 2,
+      'default': None,
       'id': 434,
       'caption': '''Control use of the WebUSB API''',
       'tags': ['website-sharing'],
@@ -5992,6 +5994,7 @@
         'per_profile': True,
       },
       'example_value': 2,
+      'default': None,
       'id': 751,
       'caption': '''Control use of the Serial API''',
       'tags': ['website-sharing'],
@@ -6079,6 +6082,7 @@
         'per_profile': True,
       },
       'example_value': 2,
+      'default': None,
       'id': 773,
       'caption': '''Control use of the File System API for reading''',
       'tags': ['website-sharing'],
@@ -6112,6 +6116,7 @@
         'per_profile': True,
       },
       'example_value': 2,
+      'default': 3,
       'id': 774,
       'caption': '''Control use of the File System API for writing''',
       'tags': ['website-sharing'],