Optimize Cadence/Solidity code to use tuples for ABI encoding/decoding

[m-Peter]

The following Cadence/Solidity method: https://github.com/onflow/FlowYieldVaultsEVM/blob/8ce7203bec6f30e6b7dfc80f2cbf984951f1bdd0/cadence/contracts/FlowYieldVaultsEVM.cdc#L1289C56-L1289C82, could benefit from an optimization boost, by using the newly-added functionality that ABI encodes/decodes Solidity tuples into Cadence.

[liobrasil]

@m-Peter https://github.com/onflow/flow-go/blob/master/fvm/evm/stdlib/contract.cdc#L766-L777 for reference.
We can now call this function in Cadence directly instead of using the EVM contract. This function is made available on the EVM system contract and It's not a general function that is available as part of the standard-library of Cadence. Here we're interested in getPendingRequestsUnpacked : we don't need to unpack anymore with the new version of the encodeABIWithSignature function to decode the tuples from Solidity.