Fix issue with saving admins before finishing loading.

Fix issue with saving admins before finishing loading.

Saving device policy managers settings to clear out
password stats was happening before initializing mAdminList
so could wipe active admins.

Test: manual - flash with N2G05C add google account with dmagent flash wth this fix, check dmagent is still an active admin, reboot check admin is still active.
Test: runtest -c com.android.server.devicepolicy.DevicePolicyManagerTest frameworks-services

Bug: 34277435
Change-Id: I13660b47f30e9aba001eb13f2e457c3b3f36da3e
(cherry picked from commit adbda7474cc1968b66e9948aee566dc346e71340)