Change dataDir to data_dir to match Rust naming scheme

src/utils/themes.ts

@@ -39,7 +39,7 @@ const defaultTheme = {
 export async function getThemeList() {
   // Do some invoke to backend to get the theme list
   const themes = await invoke('get_theme_list', {
-    dataDir: `${await dataDir()}/cultivation`
+    data_dir: `${await dataDir()}/cultivation`
   }) as BackendThemeList[]
   const list: ThemeList[] = [
     // ALWAYS include default theme