Describe the bug
When getting the resolved registry output, fields such as the brief field which had an empty string value are dropped. This causes a problem when trying to read in the resolved registry json or format as it is looking for required fields which are not present

To Reproduce
Steps to reproduce the behavior:

1. run weaver registry resolve and output to file
2. read in the outputted file and try to deserialize into a ResolvedRegistry struct
3. should receive an error about fields not found

Expected behavior
Should be able to deserialize back into a ResolvedRegistry structure when read from file

Additional context
I am trying to use the ResolvedRegistry struct as a catalog to generate otlp signals for a load generator