ci-azure - Skip the Azure runner matrix on Dependabot PRs

Dependabot bumps only touch action pins, and the earlier fixes (#10566,
53ea454) gated azure-migration-tests instead of ci-azure, which is the
workflow that actually acquires the Azure VMSS pools and went red on #10663.
Gate authorize (every matrix job needs it) and the supersede helper on the
actor, the same way azure-migration-tests already does.

(do Get-DbaBuild)

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Mye3A1CnBn1pnEQnFEE7Ze

Author: claude

.github/workflows/ci-azure-supersede.yml

@@ -33,7 +33,8 @@ concurrency:
 jobs:
   supersede:
     # Fork PRs get a read-only token that cannot cancel runs; their lanes keep FIFO.
-    if: github.event.pull_request.head.repo.full_name == github.repository
+    # Dependabot PRs never start a ci-azure run, so there is nothing to supersede.
+    if: github.event.pull_request.head.repo.full_name == github.repository && github.actor != 'dependabot[bot]'
     runs-on: ubuntu-latest
     timeout-minutes: 3
     steps:

.github/workflows/ci-azure.yml

@@ -74,6 +74,11 @@ env:
 
 jobs:
   authorize:
+    # Dependabot only ever bumps action pins, and its runs get no repository secrets.
+    # Every job below depends on authorize, so skipping it here keeps the whole matrix
+    # off the Azure runner pools. azure-migration-tests already skips the same way; the
+    # earlier attempts at this only patched that file, which is why it kept firing.
+    if: github.actor != 'dependabot[bot]'
     runs-on: ubuntu-latest
     timeout-minutes: 2
     outputs: