JSON unpacking doesn't seem to work in OTLP

[kentquirk]

According to this conversation, this code should (maybe!) be creating maps, not strings.

Investigate JSON values in OTLP with .NET object types. Do we properly unpack the attributes in the object?

[cartermp]

More motivation: https://houndsh.slack.com/archives/C4M02EG83/p1660579900509249

[cartermp]

For any non-Honeycomb viewers - the issue is that OTLP doesn't distinguish between a string and a json-encoded string. And it's incredibly expensive for us to scan every string for every attribute and try to parse out JSON. There are options we can pursue to enable JSON unpacking, but none are particularly amazing and do require some up-front work on behalf of end-users.

There's a discussion on enabling object types for attributes in OTLP that you can follow along here: open-telemetry/opentelemetry-specification#376