Fix an issue where we might load bubbles with an invalid user id

The existing code that handles removing bubbles for removed users
is dependent on the volatile repository having data. The volatile
repository will only have data if the bubble overflow had previously
been loaded.

This means if you removed an account that has bubbles previously
saved in XML, but hadn't received any bubbles before that
(i.e. never loaded bubble overflow, volatile repository
is not populated), next time you receive a bubble, we'd still
try to load that bubble for an account no longer on the device. This
would happen because we'd try to remove the bubble but the volatile
repository wouldn't have any data so we'd never update the XML.

This CL fixes this issue by passing active accounts to the overflow
loading method & when it reads from disc, it'll go through the list
of bubbles loaded and remove any that don't have a valid user. Then
it persists that new list to disk (if anything changed).

Test: atest BubbleDataRepositoryTest
Test: manual - have a user with a work profile
             - get bubbles on the work profile, dismiss them
             - reboot the device
             - delete the work profile
             - get a bubble on the main user
             => observe that there is no crash
Bug: 285409137
Change-Id: Ide5ca24e88e5e81a0a3b24cd48e2905ea1e5b28e