Return alias as None for new discovery devices before update (#627)

* Trim the length of the unavailable device alias

* Update to use short mac as auth required alias

* Update to return alias as none

kasa/discover.py

@@ -1,6 +1,5 @@
 """Discovery module for TP-Link Smart Home devices."""
 import asyncio
-import base64
 import binascii
 import ipaddress
 import logging
@@ -35,9 +34,6 @@ _LOGGER = logging.getLogger(__name__)
 OnDiscoveredCallable = Callable[[SmartDevice], Awaitable[None]]
 DeviceDict = Dict[str, SmartDevice]
 
-UNAVAILABLE_ALIAS = "Authentication required"
-UNAVAILABLE_NICKNAME = base64.b64encode(UNAVAILABLE_ALIAS.encode()).decode()
-
 
 class _DiscoverProtocol(asyncio.DatagramProtocol):
     """Implementation of the discovery protocol handler.
@@ -463,9 +459,7 @@ class Discover:
         device = device_class(config.host, protocol=protocol)
 
         di = discovery_result.get_dict()
-        di["model"] = discovery_result.device_model
-        di["alias"] = UNAVAILABLE_ALIAS
-        di["nickname"] = UNAVAILABLE_NICKNAME
+        di["model"], _, _ = discovery_result.device_model.partition("(")
         device.update_from_discover_info(di)
         return device