Reland "Add DedicatedMediaServiceThread to test config."

This is a reland of commit 0e5fb69bc93171a8623cda64a6e1bca466388442

Original change's description:
> Add DedicatedMediaServiceThread to test config.
>
> D3D11VideoDecoderUseSharedHandle is not enabled for the test, which is
> still blocked by some of the dawn test failures.
>
> Bug: 1377220
> Change-Id: I885bce2408dbc4ace3289c27acada20b78d9decb
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5556428
> Commit-Queue: Jianlin Qiu <jianlin.qiu@intel.com>
> Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1335106}

Bug: 1377220
Change-Id: If890657ec9319b38b3a7d37adeb098dc69fc79e4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5785059
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Commit-Queue: Jianlin Qiu <jianlin.qiu@intel.com>
Cr-Commit-Position: refs/heads/main@{#1340764}