Add actionlint workflow to lint GitHub Actions workflows (Azure#49563)

Add actionlint configuration, problem matcher, and workflow to
automatically lint GitHub Actions workflow files on pushes to main
and pull requests that modify .github/ files.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: raych1

.github/actionlint.yaml

@@ -0,0 +1,3 @@
+self-hosted-runner:
+  labels:
+    - 1ES.Pool=azsdk-pool-github-runners

.github/matchers/actionlint.json

@@ -0,0 +1,17 @@
+{
+  "problemMatcher": [
+    {
+      "owner": "actionlint",
+      "pattern": [
+        {
+          "regexp": "^(?:\\x1b\\[\\d+m)?(.+?)(?:\\x1b\\[\\d+m)*:(?:\\x1b\\[\\d+m)*(\\d+)(?:\\x1b\\[\\d+m)*:(?:\\x1b\\[\\d+m)*(\\d+)(?:\\x1b\\[\\d+m)*: (?:\\x1b\\[\\d+m)*(.+?)(?:\\x1b\\[\\d+m)* \\[(.+?)\\]$",
+          "file": 1,
+          "line": 2,
+          "column": 3,
+          "message": 4,
+          "code": 5
+        }
+      ]
+    }
+  ]
+}

.github/workflows/actionlint.yml

@@ -0,0 +1,35 @@
+name: Actionlint
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - .github/**
+  pull_request:
+    paths:
+      - .github/**
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+        with:
+          sparse-checkout: |
+            .github
+
+      # Content copied from https://raw.githubusercontent.com/rhysd/actionlint/2ab3a12c7848f6c15faca9a92612ef4261d0e370/.github/actionlint-matcher.json
+      - name: Add ActionLint Problem Matcher
+        run: echo "::add-matcher::.github/matchers/actionlint.json"
+
+      - name: Lint workflows
+        uses: docker://rhysd/actionlint:1.7.12@sha256:b1934ee5f1c509618f2508e6eb47ee0d3520686341fec936f3b79331f9315667
+        with:
+          args: -color -verbose