Fixed N+1 query occurrence in the /api/v1/facility/

[dhruv-goyal-10]

Changes Made

Annotated the count of beds & patients in Facility Queryset, which were causing N + 1 query problem.

Associated Issue

• Fixes #2256

Merge Checklist

• [X] Tests added/fixed
• [ ] Update docs in /docs
• [X] Linting Complete
• [ ] Any other necessary step

@coronasafe/care-backend-maintainers @coronasafe/care-backend-admins