[docs] Update location.mdx

[korpan]

Why

copied code is different from visible snippet which is confusing and does not work

How

just change to mdx

Test Plan

compare code in snippet and what is copied by clicking copy

Checklist

• Documentation is up to date to reflect these changes (eg: https://docs.expo.dev and README.md).
• Conforms with the Documentation Writing Style Guide
• This diff will work correctly for npx expo prebuild & EAS Build (eg: updated a module plugin).

[amandeepmittal]

When you mention copied code doesn't, do you mean you are copying the code from the block in a project on a local machine?

Assuming that's what you meant, we use expo-device package because it doesn't work on Expo Snack (snack.expo.dev). I can understand it can b confusing the copied code is different from what you are seeing so mentioning this in the example would be a good way to convey that info.