webfakes app fails to start with test coverage GH action

[juliasilge]

I see an error like this for tests that use webfakes on only the test coverage GH action:

── Error ('test-board_url.R:94:3'): can download pin from versioned board_folder ──
Error in `self$start()`: webfakes app subprocess did not start :(

Here are some examples:

• https://github.com/r-lib/webfakes/actions/runs/8858220716/job/24326597179
• https://github.com/rstudio/pins-r/actions/runs/9492349650/job/26159344091

[gaborcsardi]

This is not really a bug, but covr makes starting the subprocess very slow, probably because it needs to copy the instrumented R code, with source references, to the subprocess.

Fix here: rstudio/pins-r#854

I'll also increase the default timeout in covr.

[gaborcsardi]

Very large timeout now in covr: 9bc2a03