Revert of WebFonts intervention v2: disable the feature on Android perf test

testing/variations/fieldtrial_testing_config_android.json

 {
     "AllBookmarks": [
         {
             "disable_features": [
                 "AllBookmarks"
             ],
             "group_name": "Disabled"
         }
     ],
     "AndroidSessionNotifications": [
@@ skipping 564 matching lines @@
     "VarationsServiceControl": [
         {
             "group_name": "Interval_30min",
             "params": {
                 "fetch_period_min": "30"
             }
         }
     ],
     "WebFontsInterventionV2": [
         {
-            "group_name": "Disabled"
+            "group_name": "Enabled-slow2g"
         }
     ],
     "WebRTC-EnableWebRtcEcdsa": [
         {
             "enable_features": [
                 "WebRTC-EnableWebRtcEcdsa"
             ],
             "group_name": "Enabled"
         }
     ],
     "WebRTC-LocalIPPermissionCheck": [
         {
             "group_name": "Enabled"
         }
     ],
     "WebRTC-PeerConnectionDTLS1.2": [
         {
             "group_name": "Enabled"
         }
     ],
     "use-new-media-cache": [
         {
             "enable_features": [
                 "use-new-media-cache"
             ],
             "group_name": "Enabled"
         }
     ]
 }