Wrapped Cells and Default Row Height

[oleibman]

Fix #4584. As discussed there, MS has implemented this situation in a way that I frankly do not understand. Marking a row with a wrapped cell to not use the default row height seems to affect every other populated row. Very odd. Nevertheless, adding a new customFormat boolean property to RowDimension seems to be a way to resolve this problem. Note that the Xml generated by Excel already outputs a customFormat attribute when a style is applied to a row. This PR just adds that property for when it is needed for rowHeight. It need not, and should not, be set by the application when a style is applied to the row; PhpSpreadsheet will take care of that on its own.

Although the problem was raised for Xlsx format (I think), I investigated other relevant output formats as well. Html tends to do its own cell wrapping. I think the results after this change match the results before.

Xls already handled the output side of this situation without difficulty. A change was needed on the input side, and is included as part of this PR.

Ods did not handle default row height at all. As with other style properties, it is difficult to handle this on the input side, and this PR does nothing to improve that situation. However, we are, at least, able to provide some relief on the output side. Not complete relief - in order to apply the default size to unpopulated rows, we'd need to at least populate them with the table:number-rows-repeated attribute, and that has often been a source of problems, so I'm not willing to go there yet. This PR just ensures that all populated rows will have the correct height.

This is:

• a bugfix
• a new feature
• refactoring
• additional unit tests

Checklist:

• Changes are covered by unit tests
  • Changes are covered by existing unit tests
  • New unit tests have been added
• Code style is respected
• Commit message explains why the change is made (see https://github.com/erlang/otp/wiki/Writing-good-commit-messages)
• CHANGELOG.md contains a short summary of the change and a link to the pull request if applicable
• Documentation is updated as necessary

Why this change is needed?

Provide an explanation of why this change is needed, with links to any Issues (if appropriate).
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