chore(deps): bump @prisma/client from 6.19.0 to 7.3.0 in /backend

Bumps [@prisma/client](https://github.com/prisma/prisma/tree/HEAD/packages/client) from 6.19.0 to 7.3.0.
- [Release notes](https://github.com/prisma/prisma/releases)
- [Commits](https://github.com/prisma/prisma/commits/7.3.0/packages/client)

---
updated-dependencies:
- dependency-name: "@prisma/client"
  dependency-version: 7.3.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

backend/package-lock.json

@@ -29,7 +29,7 @@
     "seed": "ts-node prisma/seed.ts"
   },
   "dependencies": {
-    "@prisma/client": "^6.19.0",
+    "@prisma/client": "^7.3.0",
     "bcryptjs": "^3.0.3",
     "cors": "^2.8.5",
     "dotenv": "^17.2.3",