Ensure Electron binary is downloaded before AppArmor setup in CI

Electron 42 no longer downloads the binary during npm install.
Add a CI step to trigger the download before configuring the
AppArmor profile for the sandbox.

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

Author: GytisCepk

common/config/azure-pipelines/templates/integration-test-steps.yaml

@@ -34,6 +34,23 @@ steps:
       node ./common/scripts/install-run-rush webpack:test -v
     displayName: "Rush build"
 
+  # Electron 42+ no longer downloads the binary during npm install (postinstall removed).
+  # Ensure the binary is present before configuring the AppArmor profile.
+  - script: |
+      ELECTRON_DIR=$(find $PWD/common/temp/node_modules/.pnpm -path "*/electron@*/node_modules/electron" -type d 2>/dev/null | head -n 1)
+      if [ ! -d "$ELECTRON_DIR" ]; then
+        echo "##vso[task.logissue type=warning]Unable to find Electron package directory"
+      elif [ -f "$ELECTRON_DIR/dist/electron" ]; then
+        echo "Electron binary already present"
+      elif [ -f "$ELECTRON_DIR/install.js" ]; then
+        echo "Downloading Electron binary..."
+        node "$ELECTRON_DIR/install.js"
+      else
+        echo "##vso[task.logissue type=warning]Unable to find Electron install script at $ELECTRON_DIR/install.js"
+      fi
+    displayName: "Ensure Electron binary is downloaded"
+    condition: and(succeededOrFailed(), eq(variables['Agent.OS'], 'Linux'))
+
   # Starting Ubuntu 24.04, unprivileged user namespaces are restricted by default via AppArmor.
   # Electron's sandbox requires user namespaces, so we create an AppArmor profile that grants the 'userns' permission to the Electron binary.
   # See: https://discourse.ubuntu.com/t/ubuntu-24-04-lts-noble-numbat-release-notes/39890#p-99950-unprivileged-user-namespace-restrictions-15