[Go] missing tracing metadata

[pavelgj]

When Go runtime logs OT spans it's missing these things...

• genkit:state is not set -- this is perhaps OK, it may be redundant -- can be inferred from span.status field, consider deprecating it on JS side as well.
• genkit:metadata:subtype is not set for various action types (e.g. model, retriever, etc)

[falonso81]

JS.json
go.json

@apascal07
I just compared them in ´next´ branch and they have the same tracing metadata, however when error, we are missing the status.description, this MR fix that https://github.com/firebase/genkit/pull/1188/files

[yesudeep]

@alonsopec89 please add unit tests to ensure this feature works as intended.

[falonso81]

@alonsopec89 please add unit tests to ensure this feature works as intended.

@yesudeep
yes, I just push #1845