Fixing finch group name to match Finch groups

Change-Id: I5d259c9103c8e6d2853673ab6d31e956e4724f84
Reviewed-on: https://chromium-review.googlesource.com/c/1474836Reviewed-by: Brian White <bcwhite@chromium.org>
Commit-Queue: Ryan Sturm <ryansturm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#633777}

testing/variations/fieldtrial_testing_config.json

@@ -3696,7 +3696,7 @@
             ],
             "experiments": [
                 {
-                    "name": "PreviewsDisallowedOnReloads",
+                    "name": "Enabled",
                     "enable_features": [
                         "PreviewsDisallowedOnReloads"
                     ]