fix(cascader): remove outdated compatibility code(#7532) (#7534)

Author: ryne6

components/vc-cascader/Cascader.tsx

@@ -102,8 +102,6 @@ function baseCascaderProps<OptionType extends BaseOptionType = DefaultOptionType
     /** @deprecated Use `open` instead */
     popupVisible: { type: Boolean, default: undefined },
 
-    /** @deprecated Use `dropdownClassName` instead */
-    popupClassName: String,
     dropdownClassName: String,
     dropdownMenuColumnStyle: {
       type: Object as PropType<CSSProperties>,
@@ -422,11 +420,6 @@ export default defineComponent({
           'Cascader',
           '`popupVisible` is deprecated. Please use `open` instead.',
         );
-        devWarning(
-          props.popupClassName === undefined,
-          'Cascader',
-          '`popupClassName` is deprecated. Please use `dropdownClassName` instead.',
-        );
         devWarning(
           props.popupPlacement === undefined,
           'Cascader',
@@ -442,8 +435,6 @@ export default defineComponent({
 
     const mergedOpen = computed(() => (props.open !== undefined ? props.open : props.popupVisible));
 
-    const mergedDropdownClassName = computed(() => props.dropdownClassName || props.popupClassName);
-
     const mergedDropdownStyle = computed(() => props.dropdownStyle || props.popupStyle || {});
 
     const mergedPlacement = computed(() => props.placement || props.popupPlacement);
@@ -462,6 +453,7 @@ export default defineComponent({
       loadingIcon,
       dropdownMenuColumnStyle,
       customSlots,
+      dropdownClassName,
     } = toRefs(props);
     useProvideCascader({
       options: mergedOptions,
@@ -525,7 +517,6 @@ export default defineComponent({
         'popupVisible',
         'open',
 
-        'popupClassName',
         'dropdownClassName',
         'dropdownMenuColumnStyle',
 
@@ -581,7 +572,7 @@ export default defineComponent({
           emptyOptions={emptyOptions}
           // Open
           open={mergedOpen.value}
-          dropdownClassName={mergedDropdownClassName.value}
+          dropdownClassName={dropdownClassName.value}
           placement={mergedPlacement.value}
           onDropdownVisibleChange={onInternalDropdownVisibleChange}
           // Children