Rename session ending method calls to use consistent names.

* Session contains removeFromService() and destroy().
removeFromService() removes the session and also calls destroy()
* AFManagerServiceImpl has renamed methods to remove*Sessions() since
it's actually calling into removeFromService instead of just destroy().

BYPASS_INCLUSIVE_LANGUAGE_REASON=will_do_in_separate_cl

Bug: 162357598
Test: atest CtsAutoFillServiceTestCases
Change-Id: I4ddc4b863b2f3c962408dc0e54f8be5b34ee32b4