API endpoint `prefix-location-assignments` not able to filter by prefix UUID

[joewesch]

Environment

• Nautobot version (Docker tag too if applicable):
• Python version:
• Database platform, version:
• Middleware(s):

Steps to Reproduce

1. Create a Prefix with a Location assigned to it
2. Try and filter prefix to location assignments by the UUID of the prefix (e.g. api/ipam/prefix-location-assignments/?prefix=63b2b269-b33c-446e-bf34-fad097386261)

Expected Behavior

All prefix to location assignments for that prefix should be returned.

Observed Behavior

0 results are returned unless I filter by the prefix name itself (e.g. ?prefix=192.0.2.0/24)

[glennmatthews]

We either need to enhance the prefix method filter to handle UUIDs, or add a separate prefix_id ModelMultipleChoiceFilter. The location filter is using a NaturalKeyOrPKMultipleChoiceFilter so it's fine as-is.

Also, conversely, the VRFPrefixAssignmentFilterSet prefix filter only understands a PK, and doesn't understand a prefix string. So we should fix that too.