fix: add missing imports to ChemistrySampleInfoAdmin

Add missing Request and HasOne imports that were causing NameError
during test collection.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: kbighorse

admin/views/chemistry_sampleinfo.py

@@ -28,6 +28,9 @@
 - thing_id: Integer FK to Thing.id
 """
 
+from starlette.requests import Request
+from starlette_admin.fields import HasOne
+
 from admin.views.base import OcotilloModelView