valueQuery Issue for Custom API Data Source

Hey there,
We encountered some issue when implementing `valueQuery` in flexmonster.
This issue only applies for custom API data source. It works well for CSV
data source.
Here is the issue we reproduce using
https://github.com/flexmonster/api-data-source.
Steps to reproduce the issue
1. After setting up the [flexmonster's api-data-source example](https://github.com/flexmonster/api-data-source). We enabled the `valueQuery` feature as such:

--- a/server-nodejs/api/cube.js
+++ b/server-nodejs/api/cube.js
@@ -71,7 +71,8 @@ async function getFields(index) {
             "filters": {
                 "any": {
                     "members": true,
-                    "query": true
+                    "query": true,
+                    "valueQuery": true
                  }
              }
          };

2. Then we set the report fields:

{
  "dataSource": {
  "type": "api",
  "url": "http://localhost:3400/api/cube",
  "index": "fm-product-sales"
},
"slice": {
  "rows": [
    {
      "uniqueName": "Quantity"
    }
  ],
  "columns": [
    {
      "uniqueName": "[Measures]"
    }
  ],
  "measures": [
    {
      "uniqueName": "Price",
      "aggregation": "sum"
    },
    {
      "uniqueName": "Price",
      "aggregation": "average"
    },
    {
      "uniqueName": "Price",
      "aggregation": "max"
    }
  ]
},
"formats": [
  {
    "name": "",
    "maxDecimalPlaces": 2
  }
],
"version": "2.9.19",
"creationDate": "2022-03-07T03:43:27.167Z"
}

 
**Issue**
When we try to choose the value query for `Sum of Price` or `Average of Price`,
and apply, flexmonster always forcing the value query to `Max of Price`.
Seems like flexmonster keep forcing the users to choose the last aggregation of the
chosen field for value query. ie. If we set the values:
- `Sum of Price`
- `Average of Price`
- `Max of Price`
- `Count of Country`
- `Distinct Count of Country`
If we choose `Sum of Price` or `Average of Price`, flexmonster will force
`Max of Price` as the chosen `valueQeury`.
If we choose `Count of Country`, flexmonster will force
`Distinct Count of Country` as the chosen `valueQeury`.
Here is video attachment to further explain the issue:
issue_flexmonster_valueQuery.mp4.