refactor: reorganize import statements for consistency across multiple files

tests/services/test_activity_service.py

@@ -7,6 +7,9 @@ from collections.abc import AsyncGenerator
 
 import pytest
 import pytest_asyncio
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
+from sqlalchemy.pool import StaticPool
+
 from app.models.activity import Activity, ActivityType
 from app.models.base import Base
 from app.models.contact import Contact
@@ -22,8 +25,6 @@ from app.services.activity_service import (
     ActivityValidationError,
 )
 from app.services.organization_service import OrganizationContext
-from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
-from sqlalchemy.pool import StaticPool
 
 
 @pytest_asyncio.fixture()