improvement(client DIS): use ISubscribable for eventing

[jason-ha]

demonstrates an instantiation infinite recursion issue using ISubscribable over IEventProvider

@fluid-experimental/independent-state: experimental/framework/independent-state/src/test/latestValueManager.spec.ts:46:26 - error TS2589: Type instantiation is excessively deep and possibly infinite.
@fluid-experimental/independent-state: 
@fluid-experimental/independent-state: 46 const cursorUpdatedOff = cursor.events.on("updated", logClientValue);

type for events.on:

(method) ISubscribable<LatestValueManagerEvents<{ x: number; y: number; }>>.on<"updated">(eventName: "updated", listener: (update: LatestValueClientData<{
    x: number;
    y: number;
}>) => void): () => void