fix(signal_label): dispatcher unsubscribed in the cleanup

bec_widgets/widgets/utility/signal_label/signal_label.py

@@ -8,7 +8,6 @@ import numpy as np
 from bec_lib.device import Device, Signal
 from bec_lib.endpoints import MessageEndpoints
 from bec_qthemes import material_icon
-from qtpy.QtCore import Qt
 from qtpy.QtCore import Signal as QSignal
 from qtpy.QtWidgets import (
     QApplication,
@@ -483,6 +482,11 @@ class SignalLabel(BECWidget, QWidget):
             self._custom_label if self._custom_label else f"{self._default_label}:"
         )
 
+    def cleanup(self):
+        self.disconnect_device()
+        self._device_obj = None
+        super().cleanup()
+
 
 if __name__ == "__main__":
     app = QApplication(sys.argv)