Bump the production-dependencies group across 1 directory with 3 updates

Bumps the production-dependencies group with 3 updates in the /backend directory: [cron](https://github.com/kelektiv/node-cron), [eventsource](https://github.com/EventSource/eventsource) and [mongoose](https://github.com/Automattic/mongoose).


Updates `cron` from 3.3.2 to 3.5.0
- [Release notes](https://github.com/kelektiv/node-cron/releases)
- [Changelog](https://github.com/kelektiv/node-cron/blob/main/CHANGELOG.md)
- [Commits](kelektiv/node-cron@v3.3.2...v3.5.0)

Updates `eventsource` from 2.0.2 to 3.0.5
- [Release notes](https://github.com/EventSource/eventsource/releases)
- [Changelog](https://github.com/EventSource/eventsource/blob/main/CHANGELOG.md)
- [Commits](EventSource/eventsource@v2.0.2...v3.0.5)

Updates `mongoose` from 8.9.3 to 8.9.7
- [Release notes](https://github.com/Automattic/mongoose/releases)
- [Changelog](https://github.com/Automattic/mongoose/blob/master/CHANGELOG.md)
- [Commits](Automattic/mongoose@8.9.3...8.9.7)

---
updated-dependencies:
- dependency-name: cron
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: production-dependencies
- dependency-name: eventsource
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: production-dependencies
- dependency-name: mongoose
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: production-dependencies
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

backend/package-lock.json

@@ -17,13 +17,13 @@
   "dependencies": {
     "bunyan": "^1.8.15",
     "cors": "^2.8.5",
-    "cron": "^3.2.1",
+    "cron": "^3.5.0",
     "date-fns": "^4.1.0",
     "dotenv": "^16.4.5",
-    "eventsource": "^2.0.2",
+    "eventsource": "^3.0.5",
     "express": "^4.21.2",
     "express-rate-limit": "^7.4.1",
-    "mongoose": "^8.8.4",
+    "mongoose": "^8.9.7",
     "mysql2": "^3.11.4",
     "octokit": "4.1",
     "smee-client": "^2.0.4",