[Lens][Embeddable] Use reload$ api for custom component (elastic#203755)

## Summary

Fixes elastic#203457 

Use the `lastReloadRequestTime` prop to trigger a reload in place of the
legacy `searchSessionId` system.

x-pack/plugins/lens/public/react_embeddable/renderer/lens_custom_renderer_component.tsx

@@ -61,6 +61,7 @@ export function LensRenderer({
   disabledActions,
   searchSessionId,
   hidePanelTitles,
+  lastReloadRequestTime,
   ...props
 }: LensRendererProps) {
   // Use the settings interface to store panel settings
@@ -86,6 +87,11 @@ export function LensRenderer({
 
   const showPanelChrome = Boolean(withDefaultActions) || (extraActions?.length || 0) > 0;
 
+  const reload$ = useMemo(() => new BehaviorSubject<void>(undefined), []);
+  useEffect(() => {
+    reload$.next();
+  }, [reload$, lastReloadRequestTime]);
+
   // Re-render on changes
   // internally the embeddable will evaluate whether it is worth to actual render or not
   useEffect(() => {
@@ -152,6 +158,7 @@ export function LensRenderer({
           attributes: props.attributes,
         }),
         hidePanelTitle: hidePanelTitles$,
+        reload$, // trigger a reload (replacement for deprepcated searchSessionId)
       })}
       onApiAvailable={setLensApi}
       hidePanelChrome={!showPanelChrome}