ActiveModeWarden: Add null check in getCmmInRoles

Role is initialized with null in every mode manager. So, we should
handle that.

Also, fix the WifiThreadRunner.call() invocation in getConnectionInfo().

Bug: 176299374
Test: atest com.android.server.wifi
Change-Id: Iaad28026cf83ae6f27d43fefd9532fc5054e6f4b
7 files changed