chore: remove temporary helpdesk form override

[shaoster]

Problem / Motivation

django-helpdesk currently pulls in django-bootstrap4-form, which does not publish a wheel. In our Bazel/uv setup, that causes the package to be built from source during test runs, which is the workaround we need for this PR.

Upstream django-helpdesk also has a sibling django-bootstrap5-form project, so this dependency setup is likely temporary. We should keep the current PR focused on the helpdesk integration and remove the workaround later when upstream moves to the Bootstrap 5 form package.

Proposed Solution

Track the follow-up work to remove the local django-bootstrap4-form override once django-helpdesk adopts django-bootstrap5-form or otherwise no longer requires the Bootstrap 4 helper.

Acceptance Criteria

• Upstream helpdesk dependency changes are verified and the temporary override can be removed safely.
• The Bazel/uv dependency setup no longer needs a local workaround for django-bootstrap4-form.
• The helpdesk feature continues to pass tests after the dependency cleanup.

Out of Scope

• Reworking the helpdesk UI or URLs.
• Introducing a local compatibility package.
• Any broader Bazel Python toolchain migration.

[shaoster]

Blocked — waiting on upstream dependency update

This cleanup depends on django-helpdesk/django-helpdesk dropping its django-bootstrap4-form dependency (e.g., by migrating to django-bootstrap5-form or removing the Bootstrap 4 form helper entirely).

Until that happens, the local Bazel/uv override for django-bootstrap4-form must stay in place. Watch the upstream repo's releases and requirements*.txt / setup.cfg for the change, then revisit this issue.