Allow MDNSDiscoveryParticipant to scan for multiple service types

[morph166955]

Use case is AndroidTV. Currently I scan for GoogleTV and ShieldTV which have different mdns service types "_androidtvremote2._tcp.local." versus "_nv_shield_remote._tcp.local.". Unfortunately I have devices (e.g. the ShieldTV) which announce both. This is causing a duplicate entry in the inbox because representation-property only tracks based on the device type (e.g. androidtv:googletv versus androidtv:shieldtv). What I would like to do is consolidate my discovery to a single participant that can search for both and make an educated decision as to what single entry to add to the inbox based on what it gets back. From what I can tell, getServiceType() only accepts a single entry.