Fix native event metadata parsing

[ziscky]

https://app.clickup.com/t/8694tyanq

This PR addresses the issue of misrepresenting event values containing CIDs and BigInts in the parsed metadata.

1. CIDs were wrongly represented as {}.
2. BigInts were wrongly represented as the base64 encoding of the raw bytes.

Tests have also been updated accordingly.

References:

• https://github.com/filecoin-project/lotus/blob/6e13eac5d51f08d964f1338d9fab7cca42014e5c/documentation/en/actor-events-api.md?plain=1#L359
• https://github.com/ipld/go-ipld-prime/blob/master/linking/cid/HACKME.md
• https://github.com/ipld/go-ipld-prime/blob/198d7dba8fb83cf9e6c1da74d7800cb300c66433/datamodel/link.go#L12

🔗 zboto Link

[emmanuelm41]

🚀🚀

[emmanuelm41]

Amazing! Really amazing!

[emmanuelm41]

@ziscky can we update the PR description?

[emmanuelm41]

Let's fix tests first! Besides, please check int64 does not fit on JSON format. Those should be strings too :/ Check the max JSON number! Made me think we could represent numbers as strings directly. Not sure what it is easier to do.

[emmanuelm41]

Just wondering if the value can be negative, as the ipld kind is Int, and we later compare to Uint32... My only doubt here!

[ziscky]

Just wondering if the value can be negative, as the ipld kind is Int, and we later compare to Uint32... My only doubt here!

Updated to check both bounds