Revert "healthd: add stem to health@2.0-service.override [DO NOT MERGE]"

This should have been done with actual fixes to sepolicy and rc scripts.

This reverts commit 29927678.

Reason for revert: broke the build

Bug: 110228707

Change-Id: I23944d044dd2f87e6c1033ed7a4c7cf34f16247e