WifiInfo: Add isPrimary to indicate the primary connection

Also,
i) Added an onRoleChanged() method for ConcreteClientModeManager to
inform the associated ClientModeImpl of any role change events.
ii) Moved the cached APF filter application logic using the new method.
iii) set IsPrimary on WifiInfo on role changes and send network
capabilities update.

Bug: 180125982
Test: atest com.android.server.wifi
Test: atest android.net.wifi
Change-Id: I12cdeb947d6f7cc7aae744fc06c980913607871d
9 files changed