Enable Field Trial for Browser Verified Mouse User Activation Trigger

The study name is the same as the Finch experiment here:
https://critique-ng.corp.google.com/cl/323785153

Bug: 1098466
Change-Id: I86a3ad6f35bf3cf0e099d3b13c7815b6fca9dd02
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2329934
Commit-Queue: Liviu Tinta <liviutinta@chromium.org>
Reviewed-by: Brian White <bcwhite@chromium.org>
Cr-Commit-Position: refs/heads/master@{#793624}

testing/variations/fieldtrial_testing_config.json

@@ -1245,6 +1245,26 @@
             ]
         }
     ],
+    "BrowserVerifiedUserActivationMouseTrigger": [
+        {
+            "platforms": [
+                "windows",
+                "mac",
+                "chromeos",
+                "linux",
+                "android",
+                "android_weblayer"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "BrowserVerifiedUserActivationMouse"
+                    ]
+                }
+            ]
+        }
+    ],
     "CSSMatchedPropertiesCacheDependencies": [
         {
             "platforms": [