Floss: Fix LTK auth field on BlueZ conversion

Floss and BlueZ have different enum values when it come to the auth
field on the LTKs. This CL try to align the differences.

Bug: 329392926
Bug: 328129633
Test: m -j
Test: Manually migrate Floss->BlueZ and vice-versa on these devices:
      Logitech MX Master 2S, Logitech Casa Touchpad, Logitech K580,
      Logitech MX Keys, Delux M18 mouse. Verify devices works after
      the stack switch.
Tag: #floss
Flag: EXEMPT, Floss only change
Change-Id: I364965115f6f2039a72b3a39ff82f93c9075d6fe