fix: Don't add bslib-gap-spacing when card body is not fillable

[gadenbuie]

When card_body(fillable = FALSE, ...) we should not be adding the bslib-gap-spacing class to the card body container.

App Example

library(shiny)
# library(bslib)
pkgload::load_all()
library(leaflet)

ui <- page_fillable(
  card(
    class = "text-bg-light",
    # max_height = "400px",
    card_body(
      fillable = FALSE,
      h3("Lehigh University"),
      lorem::ipsum(3, 1:3 + 1),
      actionButton("visit", "Visit School")
    ),
    card_body(
      leafletOutput("map_lehigh"),
    )
  )
)

server <- function(input, output, session) {
  output$map_lehigh <- renderLeaflet({
    lat  <- 40.60682
    long <- -75.38024
    name <- "Lehigh University"

    leaflet() |>
      addTiles() |>
      setView(lng = long, lat = lat, zoom = 13) |>
      addMarkers(lng = long, lat = lat, popup = name)
  })
}

shinyApp(ui, server)

Before	After

[cpsievert]

Looks like there at least a couple other places we unconditionally add this class -- should we be doing the same there?

[gadenbuie]

Looks like there at least a couple other places we unconditionally add this class -- should we be doing the same there?

Yeah probably! If you have the time to add those to this PR, that'd be appreciated.