Row value cannot be accessed at expected key despite row object having expected keys and values

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* Operating System: MacOS BigSur 11.4
* Node Version: 20.9.0 & 16.17.0
* NPM Version: 10.1.0
* csv-parser Version: 3.0.0

### Expected Behavior

Logs the content of the object at the specified key. EG:
console.log(row['siteName'] )
would log "Your site" or "My site"

### Actual Behavior

Doesn't extract the value of the object at the given key. The value at the column "siteName" can only be extracted using `Object.keys(row)[0]` 0 being the index of the first column.

### How Do We Reproduce?

Here is the data
| siteName | July | August |
|-----------|------|--------|
| Your site | 323 | 444 |
| My site | 111 | 222 |

```
const fs = require('fs');
const csv = require('csv-parser');

const file1 = './data.csv';
let totalGenerationData = {};

// Function to read CSV and extract the column data based on siteName
function readCSV(filePath, columnName, dataObject, callback) {
fs.createReadStream(filePath)
.pipe(csv())
.on('data', (row) => {

// As expected logs :
// { 'siteName': 'My site', July: '28926', August: '37746' }
// { 'siteName': 'Your site', July: '7107', August: '9352' }
console.log(row)

//As expected logs "siteName" "siteName"
console.log(Object.keys(row)[0])

// Logs undefined undefined
console.log(row['siteName'])

// Logs "My site"
// Logs "Your site"
console.log(row[Object.keys(row)[0]])
})
}

// Read both files and compare the data
readCSV(file1, '', totalGenerationData, () => { });
```

Interestingly the bug cannot be reproduced if siteName is the last column of the csv file.

Start with the provided data.csv example and the readCSV snippet, then inspect how csv-parser constructs row keys for the first column. Reproduce the reported difference between the first and last column cases and run the project’s existing tests; done means row['siteName'] returns the expected value for both positions without breaking other columns.

Written by the indexing model from the issue text.