Remove sort accounts method from AccountTypeManager

Add a getSortedAccounts method.
sortAccounts was only called from the AccountFilterUtil loader
and could cause threading issues if there was more than loader
running at the same time.
Return copies of account lists from AccountTypeManagerImpl.

Test:
Made sure side nav still had the right account filters.

Bug: 31799230
Change-Id: I80ec22cdb4deb98a826f97ca3726c74d23e3edb1