registration_failed on register method

## Issue

hello guys, im facing a issue when i try to use the register method, i got `registration_failed`
config:
```js
const registerConfig: RegistrationConfiguration = {
issuer: ACCOUNT_URL,
redirectUrls: [REDIRECT_URL],
serviceConfiguration: {
authorizationEndpoint: `${ACCOUNT_URL}/oauth/authorize`,
registrationEndpoint: `${ACCOUNT_URL}/oauth/authorize?action=register`,
tokenEndpoint: `${ACCOUNT_URL}/oauth/token`,
},
};

method:
```js
register: async () =>
register(registerConfig)
.then(async state => {
await StorageService.setSecureValue(
homeKeys.accessToken,
state.registrationAccessToken!,
);
})
.catch(err => {
console.log(err.code);
}),
```

Start at the register(registerConfig) call and inspect the reported err.code alongside the issuer, registrationEndpoint, authorizationEndpoint, and tokenEndpoint values shown in the issue. Reproduce the registration flow with the same configuration and determine whether the failure comes from the React Native bridge or the OAuth provider; the issue is resolved when the cause is identified with provider and reproduction details.

索引モデルが issue の本文から書いたものです。