[Refactor] Update Litegraph widget types / cleanup (#3782)

src/composables/widgets/useImagePreviewWidget.ts

@@ -237,14 +237,14 @@ const renderPreview = (
 class ImagePreviewWidget implements ICustomWidget {
   readonly type: 'custom'
   readonly name: string
-  readonly options: IWidgetOptions<unknown>
+  readonly options: IWidgetOptions<string | object>
   /** Dummy value to satisfy type requirements. */
   value: string
   y: number = 0
   /** Don't serialize the widget value. */
   serialize: boolean = false
 
-  constructor(name: string, options: IWidgetOptions<unknown>) {
+  constructor(name: string, options: IWidgetOptions<string | object>) {
     this.type = 'custom'
     this.name = name
     this.options = options