asset/btc/electrum: make floatString work for float and string float

[ukane-philemon]

This PR improves the UnmarshalJSON method of type floatString.

[JoeGruffins]

Could you add a test that confirms it does what it should? I don't know exactly what we want to parse, like "1.31" and 0?

[ukane-philemon]

like "1.31" and 0

Yes, floatString should do both, master code parses only the former. This PR enables parsing both.

[buck54321]

Please provide some reasoning for why this change is needed.

[ukane-philemon]

Please provide some reasoning for why this change is needed.

I intend to use this in #2769, as a shared code since we deal with floatString there too, suggesting this as a smaller change to make floatString compatible with cases where the same fields could be represented as floats and strings depending on the asset. In other cases where we'd need this, we would simply add a type.

[buck54321]

cases where the same fields could be represented as floats and strings depending on the asset

Sorry to keep pushing on this, but can you provide an example of a response from #2769 where the type varies depending on the asset. I have never run into an api response where a single field might be different types. floatString itself might have been unnecessary to begin with, because you can e.g.

type A struct {
    AA float64 `json:"aa,string"`
}

[buck54321]

Wait. This is for electrum? What does #2769 have to do with electrum?

[ukane-philemon]

Sorry to keep pushing on this, but can you provide an example of a response from #2769 where the type varies depending on the asset. I have never run into an api response where a single field might be different types.

At one point I intended to use average_transaction_fee_24h but eventually went with suggested_transaction_fee_gwei_options that has predictable type.

The fields circled in red are not the same for other assets, I think only eth uses strings (because of the large number) and

Wait. This is for electrum? What does #2769 have to do with electrum?

I won't be using changes in this PR for #2769 anymore as I have moved on with other options available (suggested_transaction_fee_gwei_options) but I assumed the concept of floatString should handle both cases of "24.0" and 24.0.

In that note, you can proceed to close this PR if the changes are entirely not desirable or to remove floatString entirely.