Use Array.from to avoid @ts-ignore when copying i18n.locales (#82148)
### What?
Replaces:
```ts
// @ts-ignore locales are readonly
const locales: string[] = i18n.locales;
```
with:
```ts
const locales = Array.from(i18n.locales);
```
### Why?
Avoids suppressing TypeScript errors via @ts-ignore.
Array.from safely creates a mutable copy without modifying the readonly
original, making the code cleaner and more type-safe.
### How?
Used Array.from(i18n.locales) instead of a forced type assertion.<br>
<br>
No functional change, purely a lint-/type-safety improvement.
Co-authored-by: Joseph <joseph.chamochumbi@vercel.com>