fix: no openid scope crash

[DanielRivers]

Explain your changes

When no openid scope is supplied, the storage token storage fails and errors.

This resolves: kinde-oss/kinde-sveltekit-sdk#21

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[coel]

@DanielRivers, looking at the OpenID Connect spec, the openid scope is required.

If the openid scope value is not present, the behavior is entirely unspecified.

I guess we can handle it as just OAuth2, but as far as I understand we're assuming OpenID Connect, which is probably why it is assuming the id token is there.

The developer experience doesn't sound good though. Perhaps we should throw an explicit error that openid is required, or possibly we always include it for them?

[DanielRivers]

@DanielRivers, looking at the OpenID Connect spec, the openid scope is required.

If the openid scope value is not present, the behavior is entirely unspecified.

I guess we can handle it as just OAuth2, but as far as I understand we're assuming OpenID Connect, which is probably why it is assuming the id token is there.

The developer experience doesn't sound good though. Perhaps we should throw an explicit error that openid is required, or possibly we always include it for them?

I went for the approch of ensuring that openid is passed as its required as part of the spec