[Web Playground] Make `reverse_dns()` function wasm compatible

[jonathanpv]

A note for the community

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Problem

Current error message is: https://gist.github.com/jonathanpv/d619b7552e8993f27c3ce4e8c951351a (output was too long for github issue)

ref: vectordotdev/vector#14654 ref: vectordotdev/vrl#22

[JeanMertz]

A quick note here that reverse_dns isn't currently documented as an available function, due to performance issues.

Additionally, I'm uncertain if there's a way to do a reverse DNS lookup client-side? I guess you could do a regular HTTP query to the IP, and inspect the returned headers, but that's separate from an actual reverse DNS lookup (i.e. it doesn't query the actual DNS server), and I'm not even sure if that can get us what we want.

There is a project (dohjs) to do DNS queries from the client, but again, this is about the inverse of that.

We can keep this issue open to see if there are any ideas on how to tackle this, but I consider it low-priority given the above notes, and if there's no good way to solve this, I would probably morph this issue into finding a way to properly encode+document a list of functions we can/will never support in Wasm.