[ShareCCT] Add ShareByDefaultInCCT to fieldtrial testing config.

Bug: 1135311
Change-Id: I6a19811ebd86128ded2a6375313d38c55bc773d9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2561701Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Commit-Queue: Sophey Dong <sophey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833210}

testing/variations/fieldtrial_testing_config.json

@@ -6449,6 +6449,21 @@
             ]
         }
     ],
+    "ShareByDefaultInCCT": [
+        {
+            "platforms": [
+                "android"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "ShareByDefaultInCCT"
+                    ]
+                }
+            ]
+        }
+    ],
     "SharedClipboard": [
         {
             "platforms": [