Fixup DutlinkSerial initialization

Author: NickCao

packages/jumpstarter-driver-dutlink/jumpstarter_driver_dutlink/driver.py

@@ -83,16 +83,19 @@ def control(self, direction, ty, actions, action, value):
 
 
 @dataclass(kw_only=True)
-class DutlinkSerial(DutlinkConfig, PySerial):
-    url: str | None = field(init=False, default=None)
-
+class DutlinkSerialConfig(DutlinkConfig, Driver):
     def __post_init__(self):
         if hasattr(super(), "__post_init__"):
             super().__post_init__()
 
         self.url = self.tty
 
 
+@dataclass(kw_only=True)
+class DutlinkSerial(PySerial, DutlinkSerialConfig):
+    url: str | None = field(init=False, default=None)
+
+
 @dataclass(kw_only=True)
 class DutlinkPower(DutlinkConfig, PowerInterface, Driver):
     last_action: str | None = field(default=None)