HF audit zkApp docs: How to Fetch Events and Actions

[barriebyron]

Audit and update all zkApp docs for technical accuracy prior to hard fork #459 Before the HF, verify technical content in

How to Fetch Events and Actions https://docs.minaprotocol.com/zkapps/o1js/fetch-events-and-actions

144 lines https://github.com/o1-labs/docs2/blob/main/docs/zkapps/o1js/fetch-events-and-actions.mdx

[barriebyron]

Feedback from @qwadratic

its not clear how can we handle 5+ concurrent updates, not loosing actions popped out from the action stack