[Nickname Management] Add feature flag to fieldtrial_testing_config

gcl: http://google3/googledata/googleclient/chrome/finch/gcl_studies/AutofillEnableCardNicknameManagementAndUpstream.gcl

Bug:1082013

Change-Id: Ia956f6ca10d361c6ede8364d6c6862b6978e7c72
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2335405Reviewed-by: Mark Pearson <mpearson@chromium.org>
Commit-Queue: Siyu An <siyua@chromium.org>
Cr-Commit-Position: refs/heads/master@{#795081}

testing/variations/fieldtrial_testing_config.json

@@ -676,6 +676,27 @@
             ]
         }
     ],
+    "AutofillEnableCardNicknameManagementAndUpstream": [
+        {
+            "platforms": [
+                "android",
+                "android_webview",
+                "chromeos",
+                "linux",
+                "mac",
+                "windows"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "AutofillEnableCardNicknameManagement",
+                        "AutofillEnableCardNicknameUpstream"
+                    ]
+                }
+            ]
+        }
+    ],
     "AutofillEnableSurfacingServerCardNickname": [
         {
             "platforms": [