Only send staked balances for TLOS

[poplexity]

Description

We currently send the stake & liquid balances back for every token in the holders route.
We need to make Rex/staked/liquid optional for holders response and don’t send it for tokens that aren’t TLOS and don’t have them. Also don’t return liquid in that case, just total

Tasks

• Do not return liquid_balance, resource_stake & rex_stake for tokens other than TLOS

[tomtomcrypto]

I had some problem with this, messing around with oneOf and multiple schemas.. But turns out it was rather simple, all you needed was to declare the field an optional type in the response schema...