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/1105957Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Commit-Queue: Olga Sharonova <olka@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568485}

testing/variations/fieldtrial_testing_config.json

@@ -359,12 +359,13 @@
             ],
             "experiments": [
                 {
-                    "name": "AudioProcess",
+                    "name": "AudioProcess_LaunchOnStartup_v2",
                     "params": {
-                        "teardown_timeout_s": "300"
+                        "teardown_timeout_s": "0"
                     },
                     "enable_features": [
                         "AudioServiceAudioStreams",
+                        "AudioServiceLaunchOnStartup",
                         "AudioServiceOutOfProcess"
                     ]
                 }