Update django-debug-toolbar requirement in /backend

Updates the requirements on [django-debug-toolbar](https://github.com/django-commons/django-debug-toolbar) to permit the latest version.
- [Release notes](https://github.com/django-commons/django-debug-toolbar/releases)
- [Changelog](https://github.com/django-commons/django-debug-toolbar/blob/main/docs/changes.rst)
- [Commits](django-commons/django-debug-toolbar@5.0.1...6.3.0)

---
updated-dependencies:
- dependency-name: django-debug-toolbar
  dependency-version: 6.3.0
  dependency-type: direct:development
...

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Author: dependabot[bot]

backend/pyproject.toml

@@ -134,5 +134,5 @@ dev = [
     "pytest-xdist>=3.5.0",
     "websockets>=12.0",
     "typer>=0.12.3",
-    "django-debug-toolbar>=5.0.1",
+    "django-debug-toolbar>=6.3.0",
 ]