fix(editor): safari compat for lit host (#10514)

Fixed this white screen crash on mobile safari:

<img src="https://graphite-user-uploaded-assets-prod.s3.amazonaws.com/lEGcysB4lFTEbCwZ8jMv/00bffd51-8e06-4d37-88d4-6f5020cd503d.png" width="500">

blocksuite/framework/block-std/src/view/element/lit-host.ts

@@ -58,7 +58,7 @@ export class EditorHost extends SignalWatcher(
     }
 
     const widgetViews = this.std.provider.getAll(WidgetViewIdentifier);
-    const widgets = widgetViews.entries().reduce(
+    const widgets = Array.from(widgetViews.entries()).reduce(
       (mapping, [key, tag]) => {
         const [widgetFlavour, id] = key.split('|');
         if (widgetFlavour === flavour) {