Excel workbook exported by SimpleExcelDataModelExporterProviderService does not have headers in 'Enumerations' sheet

[Sunspark]

Describe the bug
Excel workbook exported by SimpleExcelDataModelExporterProviderService does not have headers in 'Enumerations' sheet. This causes an Import error when trying to import the workbook via SimpleExcelDataModelImporterProviderService.

To Reproduce
Steps to reproduce the behavior:

1. Given a running Mauro instance with a known extant model.

2. When I request to the SimpleExcelDataModelExporterProviderService ({{base_url}}/dataModels/export/uk.ac.ox.softeng.maurodatamapper.plugins.excel.datamodel/SimpleExcelDataModelExporterProviderService/4.0.1)

3. Then I should receive an Excel workbook formatted such that it is appropriate to be imported to the SimpleExcelDataModelImporterProviderService ({{base_url}}/dataModels/import/uk.ac.ox.softeng.maurodatamapper.plugins.excel.datamodel/SimpleExcelDataModelImporterProviderService/4.0.1)

4. ERROR:

• Given a file exported from the simple export service
• When I attempt to import via the simple import service
• Then I get the following error
  

5. Opening the exported model file (here called dataModellds_Simple.xlsx) shows that the 'Enumerations' sheet does indeed have no headers.
   

Expected behavior
Expected the Export service to output a workbook suitable to be imported by the Importer service.
Can confirm that manually adding the requested headers to the sheet in the workbook causes the workbook to be OK to import.

Desktop (please complete the following information):

• OS: Win10, Azure VM. Running Mauro in Docker for Windows.
• Browser: Chrome, Postman
• Version:
  mauro-data-mapper:
  image: 'maurodatamapper/mauro-data-mapper:B4.10.0_F6.6.0'
  build:
  context: mauro-data-mapper
  args:
  MDM_APPLICATION_COMMIT: 4.10.0
  MDM_UI_COMMIT: 6.6.0
  ADDITIONAL_PLUGINS: "uk.ac.ox.softeng.maurodatamapper.plugins:mdm-plugin-database-sqlserver:5.1.0;uk.ac.ox.softeng.maurodatamapper.plugins:mdm-plugin-csv:3.0.0;uk.ac.ox.softeng.maurodatamapper.plugins:mdm-plugin-database-postgresql:4.0.0;uk.ac.ox.softeng.maurodatamapper.plugins:mdm-plugin-excel:4.0.1"
  MDM_UI_THEME_NAME: "default"