Enable paymaster integration

[petertonysmith94]

Summary

We've integrated the gasless paymaster with SwayFarm (FuelLabs/sway-farm#91), but were unable to enable the Fuel wallet or any predicate-based (EVM, Solana, etc) wallets. The most up to date integration on SwayFarm is the following PR (FuelLabs/sway-farm#92).

We need to make the following changes to enable these connectors:

• To allow for the Fuel wallet and predicate-based (EVM, Solana, etc) wallets to be integrated with the gasless paymaster. We need to allow functionality to-resign a transaction before submission. This can be achieved with a onBeforeSend callback on the sendTransaction method.

• The Fuel wallet requires an additional change to enable skipping of the custom fee calculates. This will skip the simulation of the transaction, which provides an overview of the transaction request. We will achieve this with a boolean flag for skipCustomFee on the sendTransaction method.

[arboleya]

cc @rishabhkeshan