wifi: Make methods deliver status synchronously (3/3)

Make all the |IWifiIface|/|IWifiRttController| HIDL interface
methods return a synchronous status code. Change from using the event
callbacks to the synchronous callbacks for delivering status.

While there,
Use the default std::string to hidl_string constructor in status
callbacks.

Bug: 32056230
Bug: 32061909
Test: Compiles
Change-Id: Ifa06a11afb085bfd6684f7b997fb730d192018ea