Ensure order of hidden network list

Framework sorts hidden network list by rules
before passing to wificond. However, the list is
disordered by using HashSet in WificondScannerImpl.
We should use List to ensure the order.

Bug: 80554433
Test: Add many hidden networks and confirm if the order of hidden
Test: unit tests
Change-Id: Id75e10c876a105673e834a505e9890dd71289148
8 files changed