ci(desktop): add HOSTED_FRONTEND_URL from GitHub Actions variables for Electron build

.github/workflows/desktop-release.yml

@@ -58,6 +58,8 @@ jobs:
       - name: Build Electron
         run: pnpm build
         working-directory: surfsense_desktop
+        env:
+          HOSTED_FRONTEND_URL: ${{ vars.HOSTED_FRONTEND_URL }}
 
       - name: Package & Publish
         run: pnpm exec electron-builder ${{ matrix.platform }} --config electron-builder.yml --publish always