autofitColumn() does not ignore hidden columns

[vaadin-bot]

Originally by wuuemm

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If aSpreadsheet (or wrapped POI's Sheet) has hidden columns, autofitColumn(int columnIndex) does not ignore them. Instead, blank vertical stripes of data-based calculated width are displayed. This method should not take columns for which isColumnHidden(int columnIndex) returns true into consideration.

-Obvious* workaround: test hidden status of a particular column in advance. if (!spreadsheet.isColumnHidden(n)) spreadsheet.autofitColumn(n);

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Imported from https://dev.vaadin.com/ issue #20110