OptionalfetchFetches OpenIdProviderMetadata from configurationUrl
See https://openid.net/specs/openid-connect-discovery-1_0.html#ProviderConfigurationRequest
an URL to the .well-known/openid-configuration of the Open ID Connect provider
Optionalfetch: typeof fetchthe OpenIdProviderMetadata of the Open ID Connect provider
Fetches the OpenID Connect provider metadata document. Injectable so tests can hold the fetch pending (the build server's test runner does not support
vi.mockmodule factories).