Remove IInputMethodManager.getEnabledInputMethodList() from greylist

App developers must never need to call this IPC method directly via
reflection.  The same functionality has been exposed as a public API
InputMethodManager#getEnabledInputMethodList() since its beggining.

Just for the record, this is what
InputMethodManager#getEnabledInputMethodList() is doing.

  public List<InputMethodInfo> getEnabledInputMethodList() {
      try {
          return mService.getEnabledInputMethodList();
      } catch (RemoteException e) {
          throw e.rethrowFromSystemServer();
      }
  }

Bug: 112722706
Test: compile
Change-Id: Idf9fa866f73dbd151bb67f60dbd57041d9055a23