Add return value (what and how much is refunded) to virtual `limit_order_cancel` operation

When a limit order is canceled due to expiration or because it is too small to fill, a virtual limit_order_cancel operation is recorded in account history. However, we didn't save the result of the operation correctly, it was always null_result ([0,{}]), but should be an asset object which indicates what and how much is refunded. This PR should fix it.

Example of old data:

a virtual limit_ordre_cancel operation

>>> get_object 1.11.1261437645
[{
"id": "1.11.1261437645",
"op": [
  2,{
    "fee": {
      "amount": 482,
      "asset_id": "1.3.0"
    },
    "fee_paying_account": "1.2.735564",
    "order": "1.7.59952142",
    "extensions": []
  }
],
"result": [
  0,{}
],
"block_num": 77727877,
"trx_in_block": 2,
"op_in_trx": 0,
"virtual_op": 0,
"is_virtual": true,
"block_time": "2023-03-19T01:54:03"
}
]

a real limit_order_cancel operation

>>> get_object 1.11.1261513074
[{
"id": "1.11.1261513074",
"op": [
  2,{
    "fee": {
      "amount": 482,
      "asset_id": "1.3.0"
    },
    "fee_paying_account": "1.2.1799499",
    "order": "1.7.519871121",
    "extensions": []
  }
],
"result": [
  2,{
    "amount": 25052176,
    "asset_id": "1.3.5589"
  }
],
"block_num": 77739593,
"trx_in_block": 0,
"op_in_trx": 3,
"virtual_op": 0,
"is_virtual": false,
"block_time": "2023-03-19T11:41:21"
}
]

bitshares / bitshares-core

Add return value (what and how much is refunded) to virtual `limit_order_cancel` operation #2729