add_CI() gives error: Can't find stat called 'stepribbon'

[kawap93]

Issue description

We use add_CI() method in Kaplan Meier Analysis and last changes in newest version 0.3.0.9003 broke up this in our dashboard.
In last commit @ddsjoberg has created custom ggproto object StatStepribbon and used that in add_CI() what cause an error Can't find stat called 'stepribbon' when visR package is not loaded.

Steps to reproduce the issue

When you will not load library(visR) then we can see that:

p <- visR::adtte %>%
  visR::estimate_KM(strata = "SEX") %>%
  visR::visr()

p %>%
visR::add_CI()

will cause the error.

What's the expected result?

We should be able to use add_CI() referring it by visR::add_CI() without loading all package.

What's the actual result?

• currently in the code it's like:

gg <- gg +
      ggplot2::geom_ribbon(ggplot2::aes(
        ymin = est.lower,
        ymax = est.upper
      ),
      stat = "stepribbon",
      na.rm = TRUE,
      show.legend = FALSE
      ) +
      ggplot2::scale_fill_manual(values = ggplot2::alpha(strata_colours, alpha))

stat = "stepribbon" cause a problem.

Additional details / screenshot

and I am asking if my pr: #448
can solve the problem?

[bailliem]

@kawap93 - could you check the current patch resolves the issue? We still need to add additional unit tests on add_CI to account for the addition of step_ribbon in issue #443

[bailliem]

close with #450