* fix(api): return HTTP response from dispatch() exception handler
BaseAPIView.dispatch() and BaseViewSet.dispatch() built the proper
error Response via handle_exception() but returned the raw exception
object instead, causing Django to raise
"TypeError: 'Exception' object is not a valid HTTP response".
Fix all six occurrences across the api, app, license and space view
bases, and add a regression test covering every affected base class.
Fixes#9157
* chore(api): add copyright header to tests/unit/views/__init__.py
The empty package init file was missing the AGPL copyright header,
failing the Copy Right Check CI (addlicense -check on all tracked
.py files).
