fix: net: use an exception in NetworkAddress::resolve()

Instead of asserting that the number of resolved ipv4 addresses is nonzero,
throw an exception. This will prevent the core from aborting if the host has
no ipv4 addresses.

The host can get into this state if the remote device loses its ipv4
advertisement midway through resolving, such as if an mdns host unpublishes
its ipv4 address as a result of going into a low-power state.

Signed-off-by: Sean Cross <sean@xobs.io>

src/lib/net/NetworkAddress.cpp

@@ -142,7 +142,9 @@ size_t NetworkAddress::resolve(size_t index)
       }
 
       resolvedAddressesCount = ipv4OnlyAddresses.size();
-      assert(resolvedAddressesCount > 0);
+      if (resolvedAddressesCount <= 0) {
+        throw ArchNetworkNameUnknownException("Hostname lookup failed");
+      }
       if (index < resolvedAddressesCount - 1) {
         m_address = ipv4OnlyAddresses[index];
       } else {