[Enrollment v2] Add v2 Enrollment to field trial testing config file

Ensures test coverage for active CryptAuth v2 Enrollment field trial.
See
https://chromium.googlesource.com/chromium/src.git/+/master/testing/variations/

See also cl/283612634.

Bug: 899080
Change-Id: Ibcee32294949352d48c8281ca793a5a7feb0321b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1950666
Auto-Submit: Josh Nohle <nohle@chromium.org>
Commit-Queue: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#721561}

testing/variations/fieldtrial_testing_config.json

@@ -1837,6 +1837,21 @@
             ]
         }
     ],
+    "CryptAuthV2Enrollment": [
+        {
+            "platforms": [
+                "chromeos"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "CryptAuthV2Enrollment"
+                    ]
+                }
+            ]
+        }
+    ],
     "D3D11VideoDecoder": [
         {
             "platforms": [