Passkeys sample should demonstrate well-known URLs

From https://developer.android.com/training/sign-in/passkeys#passkey-endpoints

Ideally with some well known URLs and Android App Links so they open up and not via Chrome

```
{
"enroll": "https://example.com/account/manage/passkeys/create"
"manage": "https://example.com/account/manage/passkeys"
}
```

Start by reading the passkey endpoints guidance linked in the issue and locating the corresponding passkeys sample. Check how the sample currently represents enroll and manage endpoints, then verify the Android App Links behavior. Done means the sample demonstrates well-known URLs that open through the app rather than Chrome.

Written by the indexing model from the issue text.