Revert "Roll Media App from 9Aak3tK4o... to 6AHX-97XE..."

This reverts commit 5e258bde.

Reason for revert: Speculative fix for test failures in https://crbug.com/1155028

Original change's description:
> Roll Media App from 9Aak3tK4o... to 6AHX-97XE...
>
> Release_Notes: http://go/media_app-x20/relnotes/Main/media_app_202012020600_RC00.html
>
> https://chrome-infra-packages.appspot.com/p/chromeos_internal/apps/media_app/app/+/6AHX-97XEsRATZXtxtSFgMgB4HPdjrF2NmTP1UctxQQC
>
> If this roll has caused a breakage, revert this CL and stop the roller
> using the controls here:
> https://skia-autoroll.corp.goog/r/media-app-chromium-autoroll
> Please CC media-app@grotations.appspotmail.com on the revert to ensure that a human
> is aware of the problem.
>
> To report a problem with the AutoRoller itself, please file a bug:
> https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug
>
> Documentation for the AutoRoller is here:
> https://skia.googlesource.com/buildbot/+doc/master/autoroll/README.md
>
> Cq-Include-Trybots: luci.chrome.try:linux-chromeos-chrome
> Bug: b/138543581,b/147599135,b/168067375,b/173978830,b/174442723,b/174536897
> Tbr: media-app@grotations.appspotmail.com
> Change-Id: Ib6c2542e28b60d8c1a04a3d21d378e4a10cac32e
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2569796
> Reviewed-by: chromium-internal-autoroll <chromium-internal-autoroll@skia-corp.google.com.iam.gserviceaccount.com>
> Commit-Queue: chromium-internal-autoroll <chromium-internal-autoroll@skia-corp.google.com.iam.gserviceaccount.com>
> Cr-Commit-Position: refs/heads/master@{#832834}

TBR=chromium-internal-autoroll@skia-corp.google.com.iam.gserviceaccount.com,chromium-scoped@luci-project-accounts.iam.gserviceaccount.com,media-app@grotations.appspotmail.com

# Not skipping CQ checks because original CL landed > 1 day ago.

TBR: sebsg@chromium.org
Bug: b/138543581
Bug: b/147599135
Bug: b/168067375
Bug: b/173978830
Bug: b/174442723
Bug: b/174536897
Change-Id: Ib1c2c8377cc932aa8223bc72282ebbf29cd77dac
Cq-Include-Trybots: luci.chrome.try:linux-chromeos-chrome
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2572164
Commit-Queue: Taylor Bergquist <tbergquist@chromium.org>
Reviewed-by: Taylor Bergquist <tbergquist@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833541}

DEPS

@@ -1636,7 +1636,7 @@ deps = {
     'packages': [
       {
         'package': 'chromeos_internal/apps/media_app/app',
-        'version': '6AHX-97XEsRATZXtxtSFgMgB4HPdjrF2NmTP1UctxQQC',
+        'version': '9Aak3tK4oVEWWOriZzuRXEUPGWU0lUrVTTcsG4FucPgC',
       },
     ],
     'condition': 'checkout_chromeos and checkout_src_internal',