App with no outputs never stops pulsing

[cpsievert]

Intentional duplicate of https://github.com/posit-dev/py-shiny/issues/1398 (the fix will derive from this repo).

library(shiny)

ui <- fluidPage(
  useBusyIndicators(),
  sliderInput("n", "Number of obs", 1, 1000, 500)
)

server <- function(input, output, session) {

}

shinyApp(ui, server)