Bump drf-spectacular-sidecar from 2026.3.1 to 2026.4.1 in /backend

Bumps [drf-spectacular-sidecar](https://github.com/tfranzel/drf-spectacular-sidecar) from 2026.3.1 to 2026.4.1.
- [Commits](tfranzel/drf-spectacular-sidecar@2026.3.1...2026.4.1)

---
updated-dependencies:
- dependency-name: drf-spectacular-sidecar
  dependency-version: 2026.4.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

backend/requirements.in

@@ -8,7 +8,7 @@ djangorestframework==3.17.1
 djangorestframework-camel-case==1.4.2
 djangorestframework-simplejwt==5.5.1
 drf-spectacular==0.29.0
-drf-spectacular-sidecar==2026.3.1
+drf-spectacular-sidecar==2026.4.1
 social-auth-app-django==5.7.0
 django-tasks==0.11.0
 discord-webhook==1.4.1

backend/requirements.txt

@@ -68,7 +68,7 @@ djangorestframework-simplejwt==5.5.1
     # via -r requirements.in
 drf-spectacular==0.29.0
     # via -r requirements.in
-drf-spectacular-sidecar==2026.3.1
+drf-spectacular-sidecar==2026.4.1
     # via -r requirements.in
 idna==3.7
     # via requests
@@ -129,8 +129,6 @@ typing-extensions==4.15.0
     # via
     #   django-stubs-ext
     #   django-tasks
-tzdata==2025.3
-    # via django
 uritemplate==4.2.0
     # via drf-spectacular
 urllib3==2.6.3