chore: helper function effective_balance_spending_without_value

[rakita]

Helper function as we have three places where value needs to be deducted.

Exctracted from #2991

[codspeed-hq]

CodSpeed Performance Report

Merging #3030 will not alter performance

_{Comparing rakita/helper-effective_balance_spending_without_value (e3ae0dc) with main (a32f8f4)}

Summary

✅ 173 untouched

[mattsse]

makes sense to me, some doc nits

[klkvr]

I'm personally fine with keeping this duplicated

[rakita]

I'm personally fine with keeping this duplicated what did you mean by duplicated?

[klkvr]

I'm personally fine with keeping this duplicated what did you mean by duplicated?

I meant that this is just a single line of code deduplicating which might not be worth the indirection and a new trait method

[rakita]

I see, as it is a trait method with a default implementation, it will not require reimplementation it. For this case it made sense to add it.

It does replace fetching two values from the same place tx.effective_*() - tx.value with one fetch tx.gas_balance_*()