Add json config for ChromeOSReinstallApps

This CL add the json ChromeOSReinstallApps json config so that we can
start ramping up the experiment.

Bug: 1154520
Change-Id: I3ee97832853334ad199657b70ac8375481f47a10
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2567144Reviewed-by: Ilya Sherman <isherman@chromium.org>
Commit-Queue: Thanh Nguyen <thanhdng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#832697}

testing/variations/fieldtrial_testing_config.json

@@ -1586,6 +1586,24 @@
             ]
         }
     ],
+    "ChromeOSReinstallApps": [
+        {
+            "platforms": [
+                "chromeos"
+            ],
+            "experiments": [
+                {
+                    "name": "enabled0DayDelay",
+                    "params": {
+                        "interaction_grace_hours": "0"
+                    },
+                    "enable_features": [
+                        "EnableAppReinstallZeroState"
+                    ]
+                }
+            ]
+        }
+    ],
     "ChromeSharingHubClankV2": [
         {
             "platforms": [