Address SonarQube code smells

I fixed the ones I could. It was quick. I think it's pointless to try to fix https://sonarqube.software.geant.org/project/issues?branch=feature%2FNAT-356-sonarqube-code-smells&id=gso&open=AYvXVReaO1NWXaQ602V0&resolved=false because it's by design, but correct me if I'm wrong.

gso/api/v1/imports.py

@@ -15,8 +15,7 @@ from gso.products.product_blocks.router import RouterRole, RouterVendor
 from gso.products.product_blocks.site import SiteTier
 from gso.services import subscriptions
 from gso.services.crm import CustomerNotFoundError, get_customer_by_name
-from gso.utils.helpers import LAGMember
-from gso.workflows.site.base_site_model import BaseSiteValidatorModel
+from gso.utils.helpers import BaseSiteValidatorModel, LAGMember
 
 router = APIRouter(prefix="/imports", tags=["Imports"], dependencies=[Depends(opa_security_default)])