Issues with font_google() file downloading #138
Description
Sometime in the last few weeks the Google Fonts API has changed their responses to include hyperlinks with a structure that sass isn't anticipating, which started leading to these unit test failures (since these tests hit an online service, we don't run them on CRAN).
https://github.com/rstudio/sass/actions/runs/8258236915/job/22590137382#step:4:220
That change in the hyperlink isn't easily reproducible (it seems to happen randomly) and is something we've actually already encountered/addressed in {bslib}'s build script to download font files (which happens to use the same approach here in sass)
rstudio/bslib#983
rstudio/bslib#1004
In that last issue, we switched the User-Agent so that we get woff2 (not woff) files, and the problem seems to have gone away (and using woff2 nowadays is likely preferable anyways), so we should do the same.
As a side effect, by fixing this issue, it should close rstudio/bslib#1000