Change RxJS subscribe usage for RxJS v8

[applejag]

Deprecation of method signature for subscribe(), need to use object with keys next, error, and complete instead of 3 separate args: https://rxjs.dev/deprecations/subscribe-arguments

Before	After
of([1,2,3]).subscribe( (v) => console.log(v), (e) => console.error(e), () => console.info('complete'), )	of([1,2,3]).subscribe({ next: (v) => console.log(v), error: (e) => console.error(e), complete: () => console.info('complete'), })

This work was started in #54 (comment) but needs to be applied throughout the entire repo