[TTS] Default-enable the Simplified Server expr

This default-enables the Simplified Server experiment.

BUG=939460

Change-Id: I4359ba4214822c4150230a394736730f02b5f593
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1891582
Auto-Submit: Donn Denman <donnd@chromium.org>
Commit-Queue: Brian White <bcwhite@chromium.org>
Reviewed-by: Theresa  <twellington@chromium.org>
Reviewed-by: Brian White <bcwhite@chromium.org>
Cr-Commit-Position: refs/heads/master@{#711341}

chrome/browser/android/chrome_feature_list.cc

@@ -382,7 +382,7 @@ const base::Feature kContextualSearchSecondTap{
     "ContextualSearchSecondTap", base::FEATURE_DISABLED_BY_DEFAULT};
 
 const base::Feature kContextualSearchSimplifiedServer{
-    "ContextualSearchSimplifiedServer", base::FEATURE_DISABLED_BY_DEFAULT};
+    "ContextualSearchSimplifiedServer", base::FEATURE_ENABLED_BY_DEFAULT};
 
 const base::Feature kContextualSearchTapDisableOverride{
     "ContextualSearchTapDisableOverride", base::FEATURE_DISABLED_BY_DEFAULT};

testing/variations/fieldtrial_testing_config.json

@@ -1687,21 +1687,6 @@
             ]
         }
     ],
-    "ContextualSearchSimplifiedServer": [
-        {
-            "platforms": [
-                "android"
-            ],
-            "experiments": [
-                {
-                    "name": "ContextualSearchSimplifiedServer",
-                    "enable_features": [
-                        "ContextualSearchSimplifiedServer"
-                    ]
-                }
-            ]
-        }
-    ],
     "ContextualSearchTranslation": [
         {
             "platforms": [