Use dataclass properties in nam discovery (#60596)

Co-authored-by: epenet <epenet@users.noreply.github.com>

homeassistant/components/nam/config_flow.py

@@ -126,7 +126,7 @@ class NAMFlowHandler(config_entries.ConfigFlow, domain=DOMAIN):
         self, discovery_info: zeroconf.ZeroconfServiceInfo
     ) -> FlowResult:
         """Handle zeroconf discovery."""
-        self.host = discovery_info[zeroconf.ATTR_HOST]
+        self.host = discovery_info.host
         self.context["title_placeholders"] = {"host": self.host}
 
         # Do not probe the device if the host is already configured