Add back-port workflow using dotnet/arcade (#25106)

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

.github/workflows/backport.yml

@@ -0,0 +1,78 @@
+name: Backport PR to branch
+on:
+  issue_comment:
+    types: [created]
+  schedule:
+    # once a day at 13:00 UTC to cleanup old runs
+    - cron: '0 13 * * *'
+
+permissions:
+  contents: write
+  issues: write
+  pull-requests: write
+  actions: write
+
+jobs:
+  label:
+    if: ${{ contains(github.event.comment.body, '/backport to') }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Add Label
+        uses: actions/github-script@v6
+        with:
+          script: |
+            const comment = context.payload.comment.body;
+            const match = comment.match(/\/backport to release\/v(\d+\.\d+)$/);
+            if (match) {
+              const version = match[1];
+              const label = `Backport-${version}.x-Consider`;
+              console.log(label);
+
+              // Add the label to the issue
+              await github.rest.issues.addLabels({
+                ...context.repo,
+                issue_number: context.issue.number,
+                labels: [label],
+              });
+            } else {
+              throw new Error("No version found in comment.  Expected: /backport to release/vN.N");
+            }
+  backport:
+    if: ${{ contains(github.event.comment.body, '/backport to') || github.event_name == 'schedule' }}
+    # validates our branch format and that the issue is labeled before backport
+    needs: label
+    uses: dotnet/arcade/.github/workflows/backport-base.yml@main
+    with:
+      repository_owners: 'powershell,travisez13'
+      pr_description_template: |
+        Backport of #%source_pr_number% to %target_branch%
+
+        <!--
+        DO NOT MODIFY THIS COMMENT. IT IS AUTO-GENERATED.
+        $$$originalpr:%source_pr_number%$$$
+        -->
+
+        /cc %cc_users%
+
+        ## Customer Impact
+
+        - [ ] Customer reported
+        - [ ] Found internally
+
+        [Select one or both of the boxes. Describe how this issue impacts customers, citing the expected and actual behaviors and scope of the issue. If customer-reported, provide the issue number.]
+
+        ## Regression
+
+        - [ ] Yes
+        - [ ] No
+
+        [If yes, specify when the regression was introduced. Provide the PR or commit if known.]
+
+        ## Testing
+
+        [How was the fix verified? How was the issue missed previously? What tests were added?]
+
+        ## Risk
+
+        [High/Medium/Low. Justify the indication by mentioning how risks were measured and addressed.]
+