[EG] appconfig required/optional

[openapi-pipeline-app[bot]]

Next Steps to Merge

Next steps that must be taken to merge this PR:

• ❌ This is the public specs repo main branch which is not intended for iterative development.
  You must acknowledge that you understand that after this PR is merged, you won't be able to stop your changes from being published to Azure customers.
  If this is what you intend, add PublishToCustomers label to your PR.
  Otherwise, retarget this PR onto a feature branch, i.e. with prefix release- (see aka.ms/azsdk/api-versions#release--branches).
• ❌ This PR has at least one breaking change (label: BreakingChangeReviewRequired).
  To unblock this PR, follow the process at aka.ms/brch.
• ❌ The required check named Swagger BreakingChange has failed. To unblock this PR, follow the process at aka.ms/brch.

[openapi-pipeline-app[bot]]

Generated ApiView

Language	Package Name	ApiView Link
.Net	Azure.Messaging.EventGrid.SystemEvents	https://apiview.dev/Assemblies/Review/3e102a891e5445af8be8cde833dbb702?revisionId=44ed79b144da4dc395fe7585c8605ec3
Python	azure-eventgrid	https://apiview.dev/Assemblies/Review/c554ddbabc6e40348998b1656e0ff585?revisionId=0db19d9ce9d54aeb881578911e4940d4
TypeSpec	Azure.Messaging.EventGrid.SystemEvents	https://apiview.dev/Assemblies/Review/bf48b2982ff74cd796f5900a221af2d5?revisionId=eff9d45952bf43f6b63cc9a276a1a68a
Swagger	Microsoft.EventGrid	https://apiview.dev/Assemblies/Review/8dab2e78889f4bf4a935473df37e62bf?revisionId=f46c8a657a0c42c7a6cfe8ca82ee4810