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/services/netbox_client.py

@@ -145,7 +145,7 @@ class NetboxClient:
         """Create a new device in Netbox."""
 
         # Get device type id
-        tier_info = TierInfo().get_module_by_name(f"Tier{site_tier}")
+        tier_info = TierInfo().get_module_by_name(f"tier{site_tier}")
         device_type = self.netbox.dcim.device_types.get(model=tier_info.device_type)
 
         # Get device role id
@@ -261,7 +261,6 @@ class NetboxClient:
         ):
             interface.lag = None
             interface.save()
-        return
 
     def get_available_lags(self, router_id: UUID) -> list[str]:
         """Return all available :term:`LAG`s not assigned to a device."""