fix: plugins/nomad-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/nomad-backend/package.json

@@ -22,7 +22,7 @@
     "postpack": "backstage-cli package postpack"
   },
   "dependencies": {
-    "@backstage/backend-common": "workspace:^",
+    "@backstage/backend-common": "0.24.1",
     "@backstage/config": "workspace:^",
     "@backstage/errors": "workspace:^",
     "@types/express": "*",