fix(typing): Add None guards for ORM lookups with nullable values

[JoshFerge]

Summary

Stacked on #107710. Adds explicit None checks and assertions before ORM .get(id=...) and .filter() calls where the ID could be None, replacing # type: ignore[misc].

Changes

• vsts/client.py — guard identity_id is None before .get()
• vercel/integration.py — extract and check user_id before .get()
• user_authenticator_enroll.py — assert request.user.id is not None
• organization_trace_item_attributes.py — assert organization_id is not None
• organization_group_search_views_starred.py — assert request.user.id is not None
• debug_files.py — extract request.GET.get("id") into variable
• user_option.py — use project_id=project.id for HybridCloudForeignKey

Test plan

• mypy passes on all changed files
• Pre-commit hooks pass

[JoshFerge]

Split into individual PRs against master: #107740, #107741, #107742, #107743, #107744, #107745, #107746