object_usage_linter should warn about missing packages

[AshesITR]

When getting Namespace exports for library calls fails, this is currently silent. This can cause confusing lints for scripts, e.g.

library(tibble) # and lintr is run where tibble is not installed

f <- function() {
  tibble(x = 42L)
}

In practice, this can easily occur when working with renv and pre-commit because the latter pulls packages from the system library by default instead of from a local renv

[MichaelChirico]

One thing about warning is it may not be surfaced to the user (e.g. if the backend process of the IDE ignores any condition < error). Maybe it could go in the lint message instead? NB: execution found calls to attach %d libraries that were not found by lintr: tibble, ...

[AshesITR]

The lint message would be repeated many times in a real script, though.

Maybe produce a separate lint on the problematic library call?