fix: 🐛 [object Object] error message fixed

[Sylvador]

Fixed error message, that's thrown when rpc throws unknown error

// logs.ts
throw new Error(`Unknown RPC error: ${error}`);
// Bugged output
Error: Unknown RPC error: [object Object]
// Fixed output
Error: Unknown RPC error: {"InsufficientFundsForRent":{"account_index":0}}