Roll Android SDK to API 36 (Baklava)

Also removes some obsolete entries from the README.chromium

Does *not* change the default target_sdk (which remains at 35). This
will be done in a separate commit.

Bug: 404818708
Change-Id: Ia8e75103c957ddc81979fd8ad8d7e4d6556bfddd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6372143
Auto-Submit: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Sam Maier <smaier@chromium.org>
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1435402}
NOKEYCHECK=True
GitOrigin-RevId: 5a5d10052bf78321d1e8d78583d5fdacf9f1182a