as.tags.bslib_sidebar guard is always FALSE

Describe the problem

R/sidebar.R:177 (as.tags.bslib_sidebar):

as.tags.bslib_sidebar <- function(x, ...) {
  if (is.null(open)) {
    open <- sidebar_open_on()
  }

There is no open in scope; the symbol resolves to base::open (a generic, never NULL), so the guard is always FALSE and sidebar_open_on() is never called. Then the local open is never used again anyway. Either it should be if (is.null(x$open)) x$open <- sidebar_open_on() or the block should be deleted.

You ask for an issue before a PR but the patch for the former option is here: https://github.com/rstudio/bslib/commit/6e76332740af9051d3a798f990216b13679186fb

Found with https://github.com/sims1253/ry :)

Start at R/sidebar.R:177 and inspect as.tags.bslib_sidebar alongside sidebar_open_on(). Compare the referenced commit with the issue's two proposed dispositions, then verify that the selected behavior is reflected in this entry point and the repository's relevant checks.