[DOC] Add workflowIds parameter to get alerts

[hdhalter]

What do you want to do?

• Request a change to existing documentation
• Add new documentation
• Report a technical problem with the documentation
• Other

Tell us about your request. Provide a summary of the request and all versions that are affected.
A parameter was added in 2.9 to get alerts: WorkflowIds (I believe this was backported to other 2.x versions)

What other resources are available? Provide links to related issues, POCs, steps for testing, etc.
Should be added here: https://opensearch.org/docs/latest/observing-your-data/alerting/api/#get-alerts
PR to add parameter is here: opensearch-project/alerting#1014
original issue: #3368