[FIX] web: fix array values export

- Install Sales and Accounting
- Go to Sales > Orders > Quotations
- Create a new quotation
- Add a product and in Order Line form, select a tax
- Save the Order Line
- Save the quotation
- Go back to quotation list
- Select (checkbox) the created quotation
- Select "Export" in Action menu
- In export wizard, choose "Excel" format and add field "Tax amount by group"
- Validate with "EXPORT TO FILE"
An error is triggered.

The issue comes from the fact that the value of "amount_by_group" is an array of tuples
and "xlwt" cannot write that type of value.

opw-2255054

closes odoo/odoo#51480

X-original-commit: dde2ca9943362b20853ab11b15fe1504c0b8d848
Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>

addons/web/controllers/main.py

@@ -1959,6 +1959,8 @@ class ExcelExport(ExportFormat, http.Controller):
         with ExportXlsxWriter(fields, len(rows)) as xlsx_writer:
             for row_index, row in enumerate(rows):
                 for cell_index, cell_value in enumerate(row):
+                    if isinstance(cell_value, (list, tuple)):
+                        cell_value = pycompat.to_text(cell_value)
                     xlsx_writer.write_cell(row_index + 1, cell_index, cell_value)
 
         return xlsx_writer.value