Revert "Revert "pm: SharedUserId: Assign seinfo using actual targetSdkVersion""

Commit 042f4bb6 'pm: Modify getPackage() to only return non-null
packages' prevents the NullPointerException. b/
This reverts commit 00b4fa8b.

Bug: 74214574
Bug: 72290969
Test: Same tests run on original commit.
Test: successfully flash and boot from bild 4504078 to ToT master.
Change-Id: Ia1e900ebe0eb8f9d10fd0eddbf658f52e1ea79b4