Dashboard format under knitr incorrectly adds a section for deactivated code cells

[coatless]

Using echo: false and editable: false to create an output-only cell, we end up with extra whitespace under the live-* format.

For example, if we have:

---
title: empty space dashboard
format: 
  live-dashboard:
    theme: yeti
engine: knitr
---

{{< include ./_extensions/r-wasm/live/_knitr.qmd >}}


```{ojs}
//| echo: false
//| output: false
1 + 1
```

```{webr}
#| echo: false
#| edit: false
#| message: false
#| output: false
library(ggplot2)
```

## Row


```{webr}
#| echo: false
#| edit: false
ggplot()
```

## Row


```{webr}
#| echo: false
#| edit: false
plot(1:5)
```

This gives:

In this case, we have two extra cells, one at the top and one at the bottom. Though, the desired outcome would just be two cells like in the usual static form:

Source code for a static dashboard

---
title: correctly spaced dashboard
format: 
  dashboard:
    theme: yeti
engine: knitr
---

```{ojs}
//| echo: false
//| output: false
1 + 1
```

```{r}
#| echo: false
#| edit: false
#| message: false
#| output: false
library(ggplot2)
```

## Row


```{r}
#| echo: false
#| edit: false
ggplot()
```

## Row


```{r}
#| echo: false
#| edit: false
plot(1:5)
```