title: ggplot2/ggsurvplot: Vectorized input to `element_text()` is not officially supported
body: <p>I'm trying to plot survival curves for a corresponding analysis using <code>survminer</code> &amp; <code>survival</code> packages. Setting <code>risk.table = TRUE</code> in the <code>ggsurvplot</code> command results in a warning saying 'Vectorized input to <code>element_text()</code> is not officially supported. Results may be unexpected or may change in future versions of ggplot2.'</p>
  <p>I also tried whether this issue occurs with other data which it does. Here's a simple reprex I ran on R version 4.0.3, Rstudio Version 1.2.5033:</p>
  <pre><code>library('survival')
  library('survminer')
  library('ggplot2')
  
  lung &lt;- survival::lung
  fit&lt;- survfit(Surv(time, status) ~ sex, data = lung)
  ggsurvplot(fit, data = lung, risk.table = TRUE)
  </code></pre>
  <p>The warning doesn't occur if <code>risk.table = FALSE</code> which is why I assume that the risktables argument somehow interferes with the ggplot2 x-axis formatting. In a discussion on github about whether vectorized input to element_text() should be supported in the future of ggplot2, developers seem to rather opt for a deprecation cycle <a href="https://github.com/tidyverse/ggplot2/issues/3492" rel="nofollow noreferrer">https://github.com/tidyverse/ggplot2/issues/3492</a>.</p>
  <p>I was wondering if there currently is some way to overcome this issue since I would want to make regular use of <code>ggsurvplot</code> and its risktables feature in the future. The issue also seems to occur for other plots created with <code>ggplot2</code> (see github discussion above). However, in the reprex, it seems to be related to an inherent argument of <code>ggsurvplot</code> which to me seems critical for future use of this function. Any supportive input would be highly appreciated.</p>