Install from download manager overrides originating pkgName

If user initiates an installation from the Downloads Manager, use the
app label of the downloads provider directly instead of relying on
originating uid to fetch an app label

Bug: 280886418
Test: Install an app from Files > Downloads. Follow repro steps in the
bug

Change-Id: Ic4e407fe141a2a7e9e0fd4054a28d48dd449395c