Derive an OAuth2Config from this Esri-style OAuth info so it can back
a real oauth2(...) provider from @honua/sdk-js/auth. Endpoints default to
the ArcGIS Portal shape (<portalUrl>/sharing/rest/oauth2/authorize and
/token); pass explicit endpoints or a redirectUri via overrides.
Derive an OAuth2Config from this Esri-style OAuth info so it can back a real
oauth2(...)provider from@honua/sdk-js/auth. Endpoints default to the ArcGIS Portal shape (<portalUrl>/sharing/rest/oauth2/authorizeand/token); pass explicit endpoints or aredirectUriviaoverrides.