Remove UserDataSnapshot entry from the testing config.

The experiment launched.

Bug: 1126640
Change-Id: I674ef2336f3f22cf3859775805ec7997a4308281
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2631929Reviewed-by: Yann Dago <ydago@chromium.org>
Commit-Queue: Caitlin Fischer <caitlinfischer@google.com>
Cr-Commit-Position: refs/heads/master@{#844122}

testing/variations/fieldtrial_testing_config.json

@@ -7213,23 +7213,6 @@
             ]
         }
     ],
-    "UserDataSnapshot": [
-        {
-            "platforms": [
-                "linux",
-                "mac",
-                "windows"
-            ],
-            "experiments": [
-                {
-                    "name": "UserDataSnapshot",
-                    "enable_features": [
-                        "UserDataSnapshot"
-                    ]
-                }
-            ]
-        }
-    ],
     "UsernameFirstFlow": [
         {
             "platforms": [