Add uid information in PackageListObserver

The uid information of a removed package cannot be retrieved by the
packageName anymore once it is removed. So it would be useful to provide
the uid of removed package in the onPackageAdded and onPackageRemoved
method of the PackageListObserver. This modification helps simplify the
design in PermissionMonitor.

Bug: 125396053
Test: dumpsys netd trafficcontroller

Change-Id: I2bd4bdf924687960a4fa3a47235bae68d885e445