Use getPackageInfoAsUser in requestBufferForProcess

Notice that the exception is caught now, so it doesn't crash the app.
And seems the buffer is used for stats only, so seems thing is still
working. But it is still good to have it fixed :)

Fix: 36349295

Test: Install Avast Passwords in work profile only, launch it.
      Observe that no more log complaining failed to get application.

Change-Id: I27b213303e9cf08c32e2ffdb7bda131c2b7f9ecb