fix: Publish WidgetPanelProps (#2210)

- Wasn't being published, needed for the DHE refactoring of core plugins
- Specifically:
https://github.com/deephaven-ent/iris/pull/2114/files#diff-536d6ac232028a4ebbafc5ca79bb1a22844488a4b628196e43056379f9326a90R17

Author: mofojed

packages/dashboard-core-plugins/src/panels/WidgetPanel.tsx

@@ -10,7 +10,7 @@ import WidgetPanelTooltip from './WidgetPanelTooltip';
 import './WidgetPanel.scss';
 import { WidgetPanelDescriptor } from './WidgetPanelTypes';
 
-type WidgetPanelProps = {
+export type WidgetPanelProps = {
   children: ReactNode;
 
   descriptor: WidgetPanelDescriptor;

packages/dashboard-core-plugins/src/panels/index.ts

@@ -19,6 +19,6 @@ export { default as PandasPanel } from './PandasPanel';
 export * from './PandasPanel';
 export { default as Panel } from './Panel';
 export * from './WidgetPanelTypes';
-export { default as WidgetPanel } from './WidgetPanel';
+export { default as WidgetPanel, type WidgetPanelProps } from './WidgetPanel';
 export { default as WidgetPanelTooltip } from './WidgetPanelTooltip';
 export { default as MockFileStorage } from './MockFileStorage';