Make chrome.experienceSamplingPrivate API available on stable channel

chrome/common/extensions/api/_permission_features.json

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This features file defines permissions for extension APIs implemented
 // under src/chrome.
 // See extensions/common/features/* to understand this file, in particular
 // feature.h, simple_feature.h, and base_feature_provider.h.
 
 // To add a new whitelisted ID, SHA-1 it and force it to uppercase. In Bash:
@@ skipping 369 matching lines @@
   "enterprise.platformKeysPrivate": {
     "channel": "stable",
     "extension_types": ["extension", "legacy_packaged_app"],
     "platforms": ["chromeos"],
     "whitelist": [
       "657FEC7E77355CA205B0E226586621F86B33F611",  // Dogfood
       "5894126C625EF31852F215ED301A5FF1F9B7D026"   // Test
     ]
   },
   "experienceSamplingPrivate": {
-    "channel": "dev",
+    "channel": "stable",
     "extension_types": ["extension"],
     "whitelist": [
       "0B5B953E53AC1859AC1DD3F67E115D1A5C2D6123"  // https://crbug.com/384635
     ]
   },
   "experimental": {
     "channel": "stable",
     "extension_types": [
       "extension", "legacy_packaged_app", "hosted_app", "platform_app"
     ]
@@ skipping 664 matching lines @@
   },
   "webRequest": {
     "channel": "stable",
     "extension_types": ["extension", "legacy_packaged_app"]
   },
   "webRequestBlocking": {
     "channel": "stable",
     "extension_types": ["extension", "legacy_packaged_app"]
   }
 }