Disable only for current account in SIM import

SIM contacts are now only disabled if they exist in CP2 in the account that
is current selected in the SimImportFragment.

Test
manual:
1. have device with multiple accounts
2. import contacts from SIM card
3. go back to SIM import screen
4. verify that contacts are disabled and unselected when account from step 2
   is selected
5. verify that contacts are enabled and selected when a different account is
   selected

Bug 31781331
Bug 32575794
Change-Id: I682c678bfccf78abfcc67cb354efe7bd92fb3676