Enable 'Password Leak Detection' in the testing config.

Bug: 986298
Change-Id: Id6dfbd2c58e76f01c45975f767ccffd24b51a945
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1790888Reviewed-by: Jan Wilken Dörrie <jdoerrie@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
Auto-Submit: Vasilii Sukhanov <vasilii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#694806}

testing/variations/fieldtrial_testing_config.json

@@ -4094,6 +4094,25 @@
             ]
         }
     ],
+    "PasswordLeakDetection": [
+        {
+            "platforms": [
+                "android",
+                "chromeos",
+                "linux",
+                "mac",
+                "windows"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "PasswordLeakDetection"
+                    ]
+                }
+            ]
+        }
+    ],
     "PasswordProtectionForEnterprise": [
         {
             "platforms": [