fix: upgrade @defra/forms-model from 3.0.438 to 3.0.440

Snyk has created this PR to upgrade @defra/forms-model from 3.0.438 to 3.0.440.

See this package in npm:
@defra/forms-model

See this project in Snyk:
https://app.snyk.io/org/alanplatt/project/1b2bf928-5fa4-4d1c-b1ab-a952af53a16b?utm_source=github&utm_medium=referral&page=upgrade-pr

Author: snyk-bot

package-lock.json

@@ -63,7 +63,7 @@
   },
   "license": "SEE LICENSE IN LICENSE",
   "dependencies": {
-    "@defra/forms-model": "^3.0.438",
+    "@defra/forms-model": "^3.0.440",
     "@defra/hapi-tracing": "^1.0.0",
     "@elastic/ecs-pino-format": "^1.5.0",
     "@hapi/boom": "^10.0.1",