`arrow-json` supports encoding binary arrays, but not decoding

[phil-opp]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.

In #5622, support for encoding binary arrays was added (via hex encoding). However, decoding is still not supported and leads to an "Binary is not supported by JSON" error. This is inconsistent and surprising.

Describe the solution you'd like

Implement decoding of hex-encoded binary arrays. The round-trip operation (encode then decode again) should succeed without errors.

Describe alternatives you've considered

• We could also remove the binary encoding again instead, so that the crate is consistent. However, given that binary data is quite common, I'm favor of keeping it and adding decode support.

Additional context

I discovered this limitation while discussing #8684

[alamb]

label_issue.py automatically added labels {'arrow'} from #8737