[piav2] Ensure correct installer name is shown in UpdateOwnership dialog

If an APK is being sideloaded, the update ownership dialog must show the
name of the app installing the APK, and not the Package Installer.

This was implemented for Pia V1 in ag/26217760

Bug: 319319384
Test: Manual. Follow repro steps from the bug
Test: atest CtsPackageInstallTestCases:UpdateOwnershipEnforcementTest
Flag: EXEMPT bugfix
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:78d9c1b780fe65c3ec11e1b7b3b363ee762fa8b0)
Merged-In: I19f39bfe0270b02c731ea990ac1e1dbe3e21d5b1
Change-Id: I19f39bfe0270b02c731ea990ac1e1dbe3e21d5b1