### Bug description

Hello,

In the HTML format, with simple callouts without titles, there is a blank space to the right of the icon and above the callout body text where a title would be:

![image](https://github.com/quarto-dev/quarto-cli/assets/41382462/7976ff85-5e2f-468f-a93e-688a963d6e09)

Simple callouts without an icon and other types of callouts look as expected without titles. I've only looked at HTML so not sure if the same issue occurs in other formats.

This appears to be new in the pre-release version (I'm using Quarto 1.4.275, the latest available as of this writing). With Quarto 1.3.361, that same callout looked like this:

![image](https://github.com/quarto-dev/quarto-cli/assets/41382462/e4359b51-10ed-4728-95b4-72f6eb055023)

Thanks very much!


### Steps to reproduce

````qmd
---
format: html
---

::: {.callout-caution appearance="simple"}
A simple callout with no title
:::

Simple callouts without icons and other types of callouts look as expected without titles:

::: {.callout-caution appearance="simple" icon="false"}
A simple callout with no title or icon
:::

::: {.callout-caution appearance="default"}
A default callout with no title
:::

::: {.callout-caution appearance="minimal"}
A minimal callout with no title
:::

::: {.callout-caution icon="false"}
A default callout with no title or icon
:::
````


### Expected behavior

I expected the body text of the callout to appear beside the callout icon.

### Actual behavior

The body text of the callout is below a blank space to the left of the icon where the callout title (if it were present) would be.

### Your environment

- IDE: RStudio 2023.03.1 Build 446
- OS: Windows 10 Pro


### Quarto check output

```bash
C:\Users\czippel\Documents>quarto check

[>] Checking versions of quarto binary dependencies...
      Pandoc version 3.1.2: OK
      Dart Sass version 1.55.0: OK
      Deno version 1.33.2: OK
[>] Checking versions of quarto dependencies......OK
[>] Checking Quarto installation......OK
      Version: 1.4.151
      Path: C:\Users\czippel\AppData\Local\Programs\Quarto\bin
      CodePage: unknown

[>] Checking basic markdown render....OK

[>] Checking Python 3 installation....(None)

      Unable to locate an installed version of Python 3.
      Install Python 3 from https://www.python.org/downloads/

[>] Checking R installation...........OK
      Version: 4.3.0
      Path: C:/Users/czippel/AppData/Local/Programs/R/R-4.3.0
      LibPaths:
        - C:/Users/czippel/AppData/Local/Programs/R/R-4.3.0/library
      knitr: 1.43
      rmarkdown: 2.22

[>] Checking Knitr engine render......OK
```
dragonstyle
2023-06-16T22:15:19Z
c-zippel
bug
v1.4
open
Spacing issue in simple callouts without titles (HTML format)
https://github.com/quarto-dev/quarto-cli/issues/5955