Virtual networks not discoverable

**Describe the bug**
Virtual networks are not discoverable on blocks if external networks with overlapping CIDRs are associated with the block.

**To Reproduce**
I was trying to associate a new set of virtual networks CIDRs to an existing block when I realized the vnets were not discoverable. While checking the external networks, I found out some of them were overlapping with the vnets that wouldn't show up.
As a test, I removed those external vnets, refreshed the IPAM page (not just the network association refresh button) and the virtual networks showed up this time.

**Expected behavior**
Have all vnets discoverable even if they are conflicting with other vnets/external networks CIDRs.