[stable5.2] fix(export): type numeric answers as numbers in exports

[solracsf]

Backport of #3368

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[Chartman123]

I'll close this one. Backports should be done automatically by the backportbot

[Chartman123]

Please add the tests here as well :)

[solracsf]

Test had been added.

Why a different test shape than main: the 5.2 service has no setCellValue() method: the typing logic is inlined in exportData(). So instead of unit-testing a method directly, the test drives the private exportData() via invokePrivate, writes a real temp spreadsheet, reloads it with IOFactory::load(), and asserts the reloaded cell's getDataType().

It verifies the type survives a real write > read round-trip through the XLSX/ODS format.