fix: plugins/azure-sites-backend/package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-TAR-15032660

Author: snyk-io[bot]

plugins/azure-sites-backend/package.json

@@ -35,7 +35,7 @@
     "@azure/arm-appservice": "^13.0.1",
     "@azure/arm-resourcegraph": "^4.2.1",
     "@azure/identity": "^3.2.1",
-    "@backstage/backend-common": "workspace:^",
+    "@backstage/backend-common": "0.24.1",
     "@backstage/config": "workspace:^",
     "@backstage/plugin-azure-sites-common": "workspace:^",
     "@types/express": "^4.17.6",