Merge "docs: Clarify when certificate is self-signed" into main am: 69bbd1c8

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/2779947



Change-Id: I58d2a525f929436b2a81b3f08a64eabb68f78ba0
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>