qml: qenetwork: fix type confusion for "server"

exc triggered when switching from same server to same server:
```
  9.43 | D | gui.qml.qenetwork | server_status updated: Connecting
  9.43 | E | network | Exception in _run_new_interface: Exception('diagnostic name not yet available?')
Traceback (most recent call last):
  File "/home/user/wspace/electrum/electrum/logging.py", line 241, in __get_logger_for_obj
    diag_name = self.diagnostic_name()
  File "/home/user/wspace/electrum/electrum/interface.py", line 555, in diagnostic_name
    return self.server.net_addr_str()
AttributeError: 'str' object has no attribute 'net_addr_str'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home/user/wspace/electrum/electrum/util.py", line 1218, in wrapper
    return await func(*args, **kwargs)
  File "/home/user/wspace/electrum/electrum/network.py", line 986, in _run_new_interface
    interface = Interface(network=self, server=server)
  File "/home/user/wspace/electrum/electrum/interface.py", line 502, in __init__
    Logger.__init__(self)
  File "/home/user/wspace/electrum/electrum/logging.py", line 232, in __init__
    self.logger = self.__get_logger_for_obj()
  File "/home/user/wspace/electrum/electrum/logging.py", line 243, in __get_logger_for_obj
    raise Exception("diagnostic name not yet available?") from e
Exception: diagnostic name not yet available?
```

electrum/gui/qml/qenetwork.py

@@ -207,16 +207,13 @@ class QENetwork(QObject, QtEventListener):
         return self._server
 
     @pyqtSlot(str, bool, bool)
-    def setServerParameters(self, server: str, auto_connect: bool, one_server: bool):
+    def setServerParameters(self, server_str: str, auto_connect: bool, one_server: bool):
         net_params = self.network.get_parameters()
+        server = ServerAddr.from_str_with_inference(server_str)
         if server == net_params.server and auto_connect == net_params.auto_connect and one_server == net_params.oneserver:
             return
-        if server != str(net_params.server):
-            try:
-                server = ServerAddr.from_str_with_inference(server)
-                if not server:
-                    raise Exception('failed to parse')
-            except Exception:
+        if server != net_params.server:
+            if server is None:
                 if not auto_connect:
                     return
                 server = net_params.server

electrum/gui/qt/network_dialog.py

@@ -462,7 +462,7 @@ class ServerWidget(QWidget, QtEventListener):
         if not self.network._was_started:
             self.update()
             return
-        server = self.server_e.text().strip()
+        server = ServerAddr.from_str_with_inference(self.server_e.text().strip())
         net_params = self.network.get_parameters()
         if server != net_params.server or self.is_auto_connect() != net_params.auto_connect or self.is_one_server() != net_params.oneserver:
             self.set_server()

electrum/interface.py

@@ -496,6 +496,7 @@ def _get_cert_path_for_host(*, config: 'SimpleConfig', host: str) -> str:
 class Interface(Logger):
 
     def __init__(self, *, network: 'Network', server: ServerAddr):
+        assert isinstance(server, ServerAddr), f"expected ServerAddr, got {type(server)}"
         self.ready = network.asyncio_loop.create_future()
         self.got_disconnected = asyncio.Event()
         self.server = server

electrum/network.py

@@ -886,6 +886,7 @@ class Network(Logger, NetworkRetryManager[ServerAddr]):
         queue interface to be started. The actual switch will
         happen when the interface becomes ready.
         """
+        assert isinstance(server, ServerAddr), f"expected ServerAddr, got {type(server)}"
         self.default_server = server
         old_interface = self.interface
         old_server = old_interface.server if old_interface else None
@@ -973,6 +974,7 @@ class Network(Logger, NetworkRetryManager[ServerAddr]):
     @ignore_exceptions  # do not kill outer taskgroup
     @log_exceptions
     async def _run_new_interface(self, server: ServerAddr):
+        assert isinstance(server, ServerAddr), f"expected ServerAddr, got {type(server)}"
         if (server in self.interfaces
                 or server in self._connecting_ifaces
                 or server in self._closing_ifaces):
@@ -1508,6 +1510,7 @@ class Network(Logger, NetworkRetryManager[ServerAddr]):
                 # FIXME this should try to honour "healthy spread of connected servers"
                 server = self._get_next_server_to_try()
                 if server:
+                    assert isinstance(server, ServerAddr), f"expected ServerAddr, got {type(server)}"
                     await self.taskgroup.spawn(self._run_new_interface(server))
         async def maintain_healthy_spread_of_connected_servers():
             with self.interfaces_lock: interfaces = list(self.interfaces.values())