infra: Enable tree-closing on official chromium CI bots

This enables tree-closing on:
https://ci.chromium.org/ui/p/chromium/builders/ci/android-official
https://ci.chromium.org/ui/p/chromium/builders/ci/linux-official
https://ci.chromium.org/ui/p/chromium/builders/ci/mac-official
https://ci.chromium.org/ui/p/chromium/builders/ci/win32-official

This would help folks prioritize fixing official-only regressions like
https://crbug.com/345514993. The builders can take a couple hours to
cycle. So official-specific regressions may be delayed in closing the
tree after the culprit CL lands. But we assume a delayed tree closure
is better than no tree closure.

Note that the following builder won't close the tree due to flaking in
a handful of recent builds due to https://crbug.com/346263463:
https://ci.chromium.org/ui/p/chromium/builders/ci/win-official

Bug: 345514934, 346263463
Change-Id: I44f07b027303409aba0f580655780aec8d528119
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5615614


Reviewed-by: Erik Staab <estaab@chromium.org>
Reviewed-by: Garrett Beaty <gbeaty@google.com>
Commit-Queue: Ben Pastene <bpastene@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1313066}