Make EditAccount show a spinner until ready

Instead of crashing if userInfo is not yet available.

statusMessage is removed for now from UserUpdated events,
and the users model items will have a "loading" property.

src/python/config_files.py

@@ -18,7 +18,7 @@ WRITE_LOCK = asyncio.Lock()
 
 @dataclass
 class ConfigFile:
-    backend:      Backend = field()
+    backend:      Backend = field(repr=False)
     filename:     str     = field()
     use_data_dir: bool    = False