Fixed flag size (#431)

## Description:
before
<img width="410" alt="スクリーンショット 2025-04-05 16 45 08"
src="https://github.com/user-attachments/assets/f4f53783-ad11-4e81-9cd3-813515610129"
/>

now
<img width="359" alt="スクリーンショット 2025-04-05 16 44 43"
src="https://github.com/user-attachments/assets/3f3f556d-8c89-4b08-9544-c93d20b516cc"
/>

Fixes #474 

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [x] I understand that submitting code with bugs that could have been
caught through manual testing blocks releases and new features for all
contributors

## Please put your Discord username so you can be contacted if a bug or
regression is found:

Aotumuri

src/client/LangSelector.ts

@@ -246,7 +246,7 @@ export class LangSelector extends LitElement {
         : {
             native: "English",
             en: "English",
-            svg: "xx",
+            svg: "uk_us_flag",
           });
 
     return html`