Fix #1582

[kbrevoort]

Summary

This is a small fix to correct a bug reported in #1582. Column widths reported in pixels were being output to LaTeX in pixels, which causes an error because LaTeX does not recognize pixel measurements. I added a line to convert the widths to pts and use those in LaTeX. I also made some corresponding changes to a small number of testthat snapshots that were expecting LaTeX output with widths expressed as pixels to now expect widths in points.

Related GitHub Issues and PRs

• Ref: #1582

Checklist

• [x ] I understand and agree to the Code of Conduct.
• [ x] I have listed any major changes in the NEWS.
• [x ] I have added testthat unit tests to tests/testthat for any new functionality.