chore: bump up supertest version to v7 (#6690)

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This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [supertest](https://togithub.com/ladjs/supertest) | [`^6.3.4` -> `^7.0.0`](https://renovatebot.com/diffs/npm/supertest/6.3.4/7.0.0) | [![age](https://developer.mend.io/api/mc/badges/age/npm/supertest/7.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://developer.mend.io/api/mc/badges/adoption/npm/supertest/7.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://developer.mend.io/api/mc/badges/compatibility/npm/supertest/6.3.4/7.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://developer.mend.io/api/mc/badges/confidence/npm/supertest/6.3.4/7.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/) |

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### Release Notes

<details>
<summary>ladjs/supertest (supertest)</summary>

### [`v7.0.0`](https://togithub.com/ladjs/supertest/releases/tag/v7.0.0)

[Compare Source](https://togithub.com/ladjs/supertest/compare/v6.3.4...v7.0.0)

-   Merge pull request [#&#8203;834](https://togithub.com/ladjs/supertest/issues/834) from Bruception/master  [`225118c`](https://togithub.com/ladjs/supertest/commit/225118c)
-   Fix TestAgent not inheriting Agent properties  [`f290431`](https://togithub.com/ladjs/supertest/commit/f290431)
-   fix: bump deps, drop Node.js v<14.16.0  [`1e18c20`](https://togithub.com/ladjs/supertest/commit/1e18c20)

</details>

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packages/backend/server/package.json

@@ -118,7 +118,7 @@
     "c8": "^9.1.0",
     "nodemon": "^3.1.0",
     "sinon": "^17.0.1",
-    "supertest": "^6.3.4"
+    "supertest": "^7.0.0"
   },
   "ava": {
     "timeout": "1m",