auto save only when its supported

src/actions/actionExport.tsx

@@ -248,7 +248,8 @@ export const actionToggleAutoSave = register({
       commitToHistory: false,
     };
   },
-  PanelComponent: ({ appState, updateData }) => (
+  PanelComponent: ({ appState, updateData }) =>
+    supported ? (
       <label style={{ display: "flex" }}>
         <input
           type="checkbox"
@@ -264,5 +265,7 @@ export const actionToggleAutoSave = register({
           <div className="TooltipIcon">{questionCircle}</div>
         </Tooltip>
       </label>
+    ) : (
+      <></>
     ),
 });

src/components/App.tsx

@@ -910,7 +910,7 @@ class App extends React.Component<ExcalidrawProps, AppState> {
       .querySelector(".excalidraw")
       ?.classList.toggle("theme--dark", this.state.theme === "dark");
 
-    if (this.state.autoSave && this.state.fileHandle) {
+    if (this.state.autoSave && this.state.fileHandle && supported) {
       try {
         this.saveLocalSceneDebounced(
           this.scene.getElementsIncludingDeleted(),