[Zine] Favicon server switch cleanup

* Enabling the feature by default
* Removing old experiment groups.

Bug: 714709
Change-Id: I7962bcba392d67402a58f89510298be034b47d11
Reviewed-on: https://chromium-review.googlesource.com/c/1259606Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Filip Gorski <fgorski@chromium.org>
Cr-Commit-Position: refs/heads/master@{#597307}

components/ntp_snippets/features.cc

@@ -54,7 +54,7 @@ const base::Feature kCategoryRanker{"ContentSuggestionsCategoryRanker",
 
 const base::Feature kPublisherFaviconsFromNewServerFeature{
     "ContentSuggestionsFaviconsFromNewServer",
-    base::FEATURE_DISABLED_BY_DEFAULT};
+    base::FEATURE_ENABLED_BY_DEFAULT};
 
 const base::Feature kRemoteSuggestionsEmulateM58FetchingSchedule{
     "RemoteSuggestionsEmulateM58FetchingSchedule",

testing/variations/fieldtrial_testing_config.json

@@ -2541,33 +2541,6 @@
             ]
         }
     ],
-    "NTPFaviconsFromNewServer": [
-        {
-            "platforms": [
-                "android"
-            ],
-            "experiments": [
-                {
-                    "name": "Enabled",
-                    "enable_features": [
-                        "ContentSuggestionsFaviconsFromNewServer"
-                    ]
-                },
-                {
-                    "name": "Enabled_10",
-                    "enable_features": [
-                        "ContentSuggestionsFaviconsFromNewServer"
-                    ]
-                },
-                {
-                    "name": "Enabled_50",
-                    "enable_features": [
-                        "ContentSuggestionsFaviconsFromNewServer"
-                    ]
-                }
-            ]
-        }
-    ],
     "NTPLaunchAfterInactivity": [
         {
             "platforms": [