Tests were broken with the latest version of gt (1.1.0)

[yihui]

While working on #587, I discovered that our tests were failing. After investigation, I found the cause was gt 1.1.0. There are a lot of changes like

- {\large Bound summary for WLR design} \\ 
+ {\fontsize{20}{25}\selectfont  Bound summary for WLR design\fontsize{12}{15}\selectfont } \\ 
- {\small WLR approximation of \textasciitilde{}wHR at bound}
+ {\fontsize{14}{17}\selectfont  WLR approximation of \textasciitilde{}wHR at bound\fontsize{12}{15}\selectfont }
  } 
- \fontsize{12.0pt}{14.4pt}\selectfont
+ \fontsize{12.0pt}{14.0pt}\selectfont

It seems most changes are related to font sizes.

When I test with gt 1.0.0 (the previous CRAN version), everything works fine.

remotes::install_version('gt', '1.0.0')

We need to check how much these changes affect the visual appearance of RTF tables, and update our snapshots accordingly.