Revert "Security fix for VPN app killable via lockscreen."

This reverts commit d7628d56.

Reason for revert: Changes in one of the file has missing dependency CLs in the 24Q2 release. We can revert the single file and the security fix still work.

Bug: 304772709
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:9daf85a51e3e57eaac806b6a437d91ee0a666fc5)
Merged-In: I55c23afc0c338c6c009b99822780f1998d4a624b
Change-Id: I55c23afc0c338c6c009b99822780f1998d4a624b