perf: use UIAppState where possible to reduce UI rerenders (#6560)

src/excalidraw-app/index.tsx

@@ -32,6 +32,7 @@ import {
   ExcalidrawImperativeAPI,
   BinaryFiles,
   ExcalidrawInitialDataState,
+  UIAppState,
 } from "../types";
 import {
   debounce,
@@ -550,7 +551,7 @@ const ExcalidrawWrapper = () => {
 
   const onExportToBackend = async (
     exportedElements: readonly NonDeletedExcalidrawElement[],
-    appState: AppState,
+    appState: Partial<AppState>,
     files: BinaryFiles,
     canvas: HTMLCanvasElement | null,
   ) => {
@@ -581,7 +582,7 @@ const ExcalidrawWrapper = () => {
 
   const renderCustomStats = (
     elements: readonly NonDeletedExcalidrawElement[],
-    appState: AppState,
+    appState: UIAppState,
   ) => {
     return (
       <CustomStats