Fix #11729 - negative value in excel export [M2.2]

[hauso]

$dataType need to be set to 'String' instead 'Number' when value contain space (eg negative number with added space)

Fixed problem with negative values in exported XML file

Description

Added correction of dataType for negative numbers

Fixed Issues (if relevant)

1. Exported Excel with negative number can't be opened by MS Office #11729: Exported Excel with negative number can't be opened by MS Office

Manual testing scenarios

1. Generate export with negative value
2. Open thru Microsoft Office XML handler with Microsoft Office Professional Plus 2013

Contribution checklist

• not automated tests was provided