Remove MyChromeEverywhere entry from testing config.

The server-side config shows that this study ended.

Bug: 1126640
Change-Id: Ib731ca75db831a4a54b9ba3bcd7b63391723f056
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2631934Reviewed-by: Siyu An <siyua@chromium.org>
Commit-Queue: Caitlin Fischer <caitlinfischer@google.com>
Cr-Commit-Position: refs/heads/master@{#844978}

testing/variations/fieldtrial_testing_config.json

@@ -4140,24 +4140,6 @@
             ]
         }
     ],
-    "MyChromeEverywhere": [
-        {
-            "platforms": [
-                "linux",
-                "mac",
-                "windows"
-            ],
-            "experiments": [
-                {
-                    "name": "Enabled",
-                    "enable_features": [
-                        "AutofillCreditCardUploadFeedback",
-                        "AutofillEnableToolbarStatusChip"
-                    ]
-                }
-            ]
-        }
-    ],
     "NTPPopularSites": [
         {
             "platforms": [