Xlsx Reader Do Not Process Printer Settings for Dataonly

[oleibman]

Fix #4477. Xlsx Spreadsheet could be loaded and saved normally, but, when the load specified Dataonly, the output file was corrupt. Reader is changed to not process Printer Settings when Dataonly is in effect.

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