MNT: update enum-button widget's button-group to use proper clicked

signal, avoid pyside6 error

Calling signal without overloaded int and expecting a button object back,
is whats specified in qt5 docs:
https://doc.qt.io/qt-5/qbuttongroup.html#buttonClicked.

This is the same in the qt6 docs, and pyside6 even throws error if signal is not
used in this correct way.

Also seems like the newer python in running pyside6 on doesn't like using enums
to index into an array, so use a map for 'class_for_type' instead.
(using the enum's '.value' should allow for indexing into an array, but imo using the map is more readable.)

pydm/widgets/enum_button.py

@@ -2,7 +2,16 @@
 
 from qtpy.QtCore import Qt, QSize, Property, Slot, QMargins
 from qtpy.QtGui import QPainter
-from qtpy.QtWidgets import QWidget, QButtonGroup, QGridLayout, QPushButton, QRadioButton, QStyleOption, QStyle
+from qtpy.QtWidgets import (
+    QWidget,
+    QButtonGroup,
+    QGridLayout,
+    QPushButton,
+    QRadioButton,
+    QStyleOption,
+    QStyle,
+    QAbstractButton,
+)
 
 from .base import PyDMWritableWidget
 from .. import data_plugins
@@ -25,7 +34,7 @@ class WidgetType(Enum):  # noqa: F811
         RadioButton = 1
 
 
-class_for_type = [QPushButton, QRadioButton]
+class_for_type = {WidgetType.PushButton: QPushButton, WidgetType.RadioButton: QRadioButton}
 
 logger = logging.getLogger(__name__)
 
@@ -74,7 +83,7 @@ def __init__(self, parent=None, init_channel=None):
         self._layout_margins = QMargins(9, 9, 9, 9)
         self._btn_group = QButtonGroup()
         self._btn_group.setExclusive(True)
-        self._btn_group.buttonClicked[int].connect(self.handle_button_clicked)
+        self._btn_group.buttonClicked.connect(self.handle_button_clicked)
         self._widget_type = WidgetType.PushButton
         self._orientation = Qt.Vertical
         self._widgets = []
@@ -379,17 +388,18 @@ def checkable(self, value):
             for widget in self._widgets:
                 widget.setCheckable(value)
 
-    @Slot(int)
-    def handle_button_clicked(self, id):
+    @Slot(QAbstractButton)
+    def handle_button_clicked(self, button):
         """
         Handles the event of a button being clicked.
 
         Parameters
         ----------
-        id : int
-            The clicked button id.
+        id : QAbstractButton
+            The clicked button button.
         """
-        self.send_value_signal.emit(id)
+        button_id = self._btn_group.id(button)  # get id of the button in the group
+        self.send_value_signal.emit(button_id)
 
     def clear(self):
         """