[PM] Get the title of the installer outside of the lock

When the system execute the archived package installation, if we load
the label of the installer in the mLock, it causes deadlock. Get the
label outside of the mLock to avoid it.

Test: atest CtsPackageManagerTestCases
Test: atest CtsPackageUninstallTestCases:ArchiveTest
Test: atest PackageArchiverTest
Bug: 331676262
Change-Id: I0f85d9aac7bd085410d77b42ff3f9fb9065d5aa9