List the caller's withdrawals awaiting a user action (prove / finalize)

Example response

{
  "withdrawals": [
    {
      "fromAddress": "0xAbCd1234AbCd1234AbCd1234AbCd1234AbCd1234",
      "toAddress": "0xAbCd1234AbCd1234AbCd1234AbCd1234AbCd1234",
      "l2TxHash": "0xabcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890ab",
      "proveTxHash": "0xabcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890ab",
      "finalizeTxHash": "0xabcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890ab"
    }
  ]
}