Update field trial config for TurnOffStreamingMediaCaching experiment

Bug: 984851
Change-Id: Iea0ec1919e8950adb01e9e2410f5268eea9d68af
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2503326Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Commit-Queue: Will Cassella <cassew@google.com>
Cr-Commit-Position: refs/heads/master@{#821526}

testing/variations/fieldtrial_testing_config.json

@@ -7135,6 +7135,25 @@
             ]
         }
     ],
+    "TurnOffStreamingMediaCaching": [
+        {
+            "platforms": [
+                "android",
+                "chromeos",
+                "linux",
+                "mac",
+                "windows"
+            ],
+            "experiments": [
+                {
+                    "name": "TurnOffStreamingMediaCaching",
+                    "enable_features": [
+                        "TurnOffStreamingMediaCachingOnBattery"
+                    ]
+                }
+            ]
+        }
+    ],
     "UnidoPreferSync": [
         {
             "platforms": [