Further improve on handling disabled localStorage

Based on the work done in commit
`a73c5490b160435a0ef5408b54185c9f698cb73f` there are a few places that
make the app not load in case dom storage aka localStorage is disabled.

src/lib/appearance.ts

@@ -7,7 +7,7 @@ type Theme = z.infer<typeof themeSchema>;
 export const followSystemTheme = storedWritable<boolean | undefined>(
   "followSystemTheme",
   boolean(),
-  !localStorage.getItem("theme"),
+  !localStorage?.getItem("theme"),
   !window.localStorage,
 );
 export const theme = storedWritable<Theme>(

src/lib/localStore.ts

@@ -92,7 +92,7 @@ export default function storedWritable<
    */
   function clear() {
     w.set(initialValue);
-    localStorage.removeItem(key);
+    if (!disableLocalStorage) localStorage.removeItem(key);
   }
 
   return {