Fix issues w/ security-related account data deletion

* Stop running syncs
* Delete all EmailProvider data except the account itself (with
  cleared sync key) and the account mailbox (necessary for syncing
  to sync after security hold is lifted

Bug: 3245779
Bug: 3253952
Change-Id: Idc208ef5ed85808b085ebab9c26a428fb0451e34
1 file changed