Merge IInputMethodManager#get{,AwareLocked}InputMethodList

This is a follow up CL to our previous CL [1], which introduced

  IInputMethodManager#getAwareLockedInputMethodList

as a variant of

  IInputMethodManager#getInputMethodList.

This CL mechanically merges those two IPC entries into one entry as
specifying

  DirectBootAwareness.AUTO

is something we can do in the IME client side, without changing any
observable semantics.

 [1]: I54d5dbec7e76d6a68935007ed3af0641f717a7c5
      04a22633

Bug: 210083408
Bug: 234882948
Test: presubmit
Change-Id: Ic02484fcbb9c1bbd8e964bb7a2f7acff904e2a33