fix: clear table placeholders when data is empty

[smakaiberriesandco]

#338
#343

[smakaiberriesandco]

when generating excel from a template with an empty list it throws an exception: ClosedXML.Excel.Exceptions.EmptyTableException: Table 'Table1' should have at least 1 row.

I updated the commit to fix that issue too.

[smakaiberriesandco]

Apologies for any confusion caused earlier (The exception mentioned above occurs only when the table range is one row larger than the row containing the placeholders).

So when table range is correct and we provide an empty list to the table, the results still display the placeholders:

With my modifications, the table rows are now cleared:

Test created, All tests have been successfully executed.

[Pankraty]

Thanks for the contribution and sorry it took me so long!