Add new stable API version 2026-09-01 for ActionGroups (ports #37313)

[thomasp98296]

ARM (Control Plane) API Specification Update

Purpose

• New API version for an existing resource provider.

Summary

This PR adds a new stable API version 2026-09-01 for the ActionGroups resource type (Microsoft.Insights), porting the reviewed and signed-off changes from #37313.

#37313 was authored against preview 2025-09-01-preview before the Insights spec was migrated to TypeSpec, and was never merged. Since TypeSpec is now the source of truth, those same changes have been re-expressed in TypeSpec and promoted to the stable 2026-09-01 version.

Changes (TypeSpec source of truth — ActionGroupsApi/*.tsp)

• Add Versions.v2026_09_01 (2026-09-01) to the version enum.
• EventHubReceiver: add resourceId (arm-id → Microsoft.EventHub/namespaces), gated @added(2026-09-01).
• LogicAppReceiver: add triggerName, gated @added(2026-09-01).
• AzureFunctionReceiver: add scope, gated @added(2026-09-01).
• Update managedIdentity description on all 5 receivers to "The principal id of the referenced managed identity."

Regenerated artifacts

• stable/2026-09-01/actionGroups.json + examples.
• preview/2024-10-01-preview/actionGroups.json — description-only update (consequence of the shared, non-versioned TypeSpec doc comment).
• readme.md — add package-2026-09-01 tag.

Note

Local tsp compile could not be run in the authoring environment (npm registry access blocked). The generated actionGroups.json and examples were produced to match the TypeSpec emitter output; please rely on CI regeneration/validation to confirm byte-exactness.

[github-actions]

Next Steps to Merge

Next steps that must be taken to merge this PR:

• ❌ This PR targets either the main branch of the public specs repo or the RPSaaSMaster branch of the private specs repo. These branches are not intended for iterative development. Therefore, you must acknowledge you understand that after this PR is merged, the APIs are considered shipped to Azure customers. Any further attempts at in-place modifications to the APIs will be subject to Azure's versioning and breaking change policies. Additionally, for control plane APIs, you must acknowledge that you are following all the best practices documented by ARM at aka.ms/armapibestpractices. If you do intend to release the APIs to your customers by merging this PR, add the PublishToCustomers label to your PR in acknowledgement of the above. Otherwise, retarget this PR onto a feature branch, i.e. with prefix release- (see aka.ms/azsdk/api-versions#release--branches).
• ❌ This PR is in purview of the ARM review (label: ARMReview). This PR must get ARMSignedOff label from an ARM reviewer.
  This PR is awaiting ARM reviewer feedback (label: WaitForARMFeedback).
  To learn when this PR will get reviewed, see ARM review queue at aka.ms/azsdk/pr-arm-review
  For details of the ARM review, see aka.ms/azsdk/pr-arm-review
  
• ❌ The required check named TypeSpec Validation has failed. Refer to the check in the PR's 'Checks' tab for details on how to fix it and consult the aka.ms/ci-fix guide

Comment generated by summarize-checks workflow run.

[github-actions]

API Change Check

APIView identified API level changes in this PR and created the following API reviews

Language	API Review for Package
TypeSpec	ActionGroupsApi
Go	sdk/resourcemanager/monitor/armmonitor
Python	azure-mgmt-monitor
Java	com.azure.resourcemanager:azure-resourcemanager-monitor

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Comment generated by After APIView workflow run.