Excel导出，Long类型改成文本导出，内容依然是科学计数法文本

### Expected behaviour

因为不想另起一行string属性，希望能直接将long的属性，转为文本输出，不要科学计数法

### Actual behaviour
样式确实转成了文本，但是内容还是科学计数法

#### package versions
Example: Magicodes.IE.Excel 2.7.4.2

### So how can we reproduce this?

```
[ExcelExporter(Name = "中文表名", TableStyle = TableStyles.Medium10)]
public class ExportModelTest3
{
///
/// 会不会转成科学计数法
///
public long CountLong { get; set; }
///
/// 会不会转成科学计数法
///
[ExporterHeader(DisplayName = "不转科学计数法", Format = "@")]
public long CountLong2 => CountLong;
}
```
```
[Fact]
public async Task ExcelExporter_标准导出()
{
//这个只是模拟数据
List dto = GetMockList();
IExcelExporter exporter = new ExcelExporter();
var data = await exporter.ExportAsByteArray(dto);
var filePath = Path.Combine("d:\\Documents\\测试数据", $"导出_{DateTime.Now:MMddHHmmss}.xlsx");
Console.WriteLine($"filePath:{filePath}");
File.WriteAllBytes(filePath, data);
Assert.True(File.Exists(filePath));

}
```