Enable Field Trial for Browser Verified Keyboard User Activation Trigger

The study name is the same as the Finch experiment here:
https://critique-ng.corp.google.com/cl/323787252

Bug: 1098467
Change-Id: I2649613121d33b3d40ba13df8b0b81f6cb1a3d76
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2329993Reviewed-by: Brian White <bcwhite@chromium.org>
Commit-Queue: Liviu Tinta <liviutinta@chromium.org>
Cr-Commit-Position: refs/heads/master@{#793592}

testing/variations/fieldtrial_testing_config.json

@@ -1225,6 +1225,26 @@
             ]
         }
     ],
+    "BrowserVerifiedUserActivationKeyboardTrigger": [
+        {
+            "platforms": [
+                "windows",
+                "mac",
+                "chromeos",
+                "linux",
+                "android",
+                "android_weblayer"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "BrowserVerifiedUserActivationKeyboard"
+                    ]
+                }
+            ]
+        }
+    ],
     "CSSMatchedPropertiesCacheDependencies": [
         {
             "platforms": [