KB: Update situation alert KB to address use case for multiple VAMC alerts

[jilladams]

Problem Statement

re: #17344 : there are use cases for VAMC Banner alerts with situation updates, where we may use that content type to publish an alert to all VAMCs. (e.g. PACT Act deadlines, digital/data security incidents, etc.)

The current KB (https://prod.cms.va.gov/help/vamc/how-to-create-a-situation-update) doesn't address this use case. When required, it's been managed via tribal knowledge, and CAIA / OCTODE VA folks need documentation around how it does / should work.

Proposed things to cover in an update:

• Use case for when this node type can / should be used for all VAMCs, and any governance for approval to do so (CAIA audience)
• What will happen in context of only 1 alert published per VAMC. Per DaveP:

  The stacked banners are a known edge case. Last summer we updated the VAMC banners to only allow one banner to be published per system. However, the logic behind it technically only restricts "one banner that is specific to this system." So banners that are published to multiple VAMC systems can co-exist with banners that are specific to one VAMC system. When we had the PACT ACT deadline extension banners up last year, we saw this happen with a VAMC that had an extreme weather event that also warranted a banner. So there are some cases where we want to allow that

• Content release implications - updates / additions of this node type will auto-trigger a content-release outside of publishing hours (CAIA audience)

Acceptance Criteria

• [ ] KB re: situation updates reflects usage for multi-VAMC use case

[jilladams]

There's a case to be made that the VAMC use case for a single Facility, vs the CAIA / OCTO use case for multi-VAMCs may warrant a separate KB? We can discuss / update ticket with wherever we land on that.