Reland "Changing AudioService experiment field trial to test service launch on startup"

This is a reland of ec3716fd

Original change's description:
> Changing AudioService experiment field trial to test service launch on startup
>
> [1] introduced AudioServiceLaunchOnStartup feature which we want to roll out
> with a new experiment group. Updating field trial to run the config on bots
> first.
>
> [1] https://chromium-review.googlesource.com/c/chromium/src/+/1104681
>
> Bug: 851611,853781
> Change-Id: I3796a8ac205a6d37706a86e8647c933ee510f41a
> Reviewed-on: https://chromium-review.googlesource.com/1105957
> Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
> Commit-Queue: Olga Sharonova <olka@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#568485}

Bug: 851611, 853781
Change-Id: Ief31b6eee175e36735946ae835175ec7c0f36d24
Reviewed-on: https://chromium-review.googlesource.com/1118985
Commit-Queue: Olga Sharonova <olka@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#572217}

testing/variations/fieldtrial_testing_config.json

@@ -416,16 +416,14 @@
             ],
             "experiments": [
                 {
-                    "name": "AudioProcess_v3",
+                    "name": "AudioProcess_LaunchOnStartup_v3",
                     "params": {
-                        "teardown_timeout_s": "900"
+                        "teardown_timeout_s": "0"
                     },
                     "enable_features": [
                         "AudioServiceAudioStreams",
+                        "AudioServiceLaunchOnStartup",
                         "AudioServiceOutOfProcess"
-                    ],
-                    "disable_features": [
-                        "AudioServiceLaunchOnStartup"
                     ]
                 }
             ]