Refactor checkbox-list custom field implementation

- Replaced the PluginIcon with EnumerationField in the custom field registration.
- Introduced CheckboxListDefaultInput component for handling checkbox list inputs.
- Updated the admin interface to include new settings for the checkbox-list custom field.
- Enhanced server-side registration to support resizable input size for the checkbox-list.

admin/src/components/CheckboxListInput.tsx

@@ -82,7 +82,7 @@ const CheckboxListInput = ({
     <Field.Root name={name} hint={hint} error={error} required={required}>
       <Field.Label action={labelAction}>{label ?? name}</Field.Label>
       {enumValues.length > 0 ? (
-        <Flex direction="column" gap={2} paddingTop={1}>
+        <Flex direction="column" gap={2} paddingTop={1} alignItems="flex-start">
           {enumValues.map((option) => (
             <Checkbox
               key={option}