Subtitles on computational generated tables remove tbl-colwidths execution option

Bug description

When I add table sub captions, it removes the column width execution option input.

Steps to reproduce

---
format:
  docx
---

```{python}
#| output: false
#| echo: false

import pandas as pd
import numpy as np
from IPython.display import Markdown, display
from tabulate import tabulate

# Create a 10x10 DataFrame with random integers between 0 and 100
data = np.random.randint(0, 100, size=(2, 2))
df = pd.DataFrame(data)
```

This removes the col-widths.
```{python}
#| echo: false
#| label: tbl-global-markets-tables
#| warning: false
#| tbl-cap: ""
#| tbl-subcap:
#|   - "Table 1"
#|   - "Table 2"
#|   - "Table 3"
#| layout-ncol: 3
#| tbl-colwidths: [80,15,15]

display(Markdown(tabulate(
    df, headers=df.columns, showindex=True)))

display(Markdown(tabulate(
    df, headers=df.columns, showindex=True)))

display(Markdown(tabulate(
    df, headers=df.columns, showindex=True)))

```

This keeps the col-widths.
```{python}
#| echo: false
#| warning: false
#| layout-ncol: 3
#| tbl-colwidths: [80,15,15]

display(Markdown(tabulate(
    df, headers=df.columns, showindex=True)))

display(Markdown(tabulate(
    df, headers=df.columns, showindex=True)))

display(Markdown(tabulate(
    df, headers=df.columns, showindex=True)))

```

Expected behavior

The colwidths should be the same for the last two cells.

Actual behavior

The col width in the first cell that displays the tables have a fixed width it looks like.

Your environment

• IDE: VSCode
  Version: 1.90.2 (Universal)
  Commit: 5437499feb04f7a586f677b155b039bc2b3669eb
  Date: 2024-06-18T22:37:41.291Z
  Electron: 29.4.0
  ElectronBuildId: 9728852
  Chromium: 122.0.6261.156
  Node.js: 20.9.0
  V8: 12.2.281.27-electron.0
  OS: Darwin arm64 22.5.0

• OS: Ventura 13.4 (22F66)

Quarto check output

Quarto 1.4.554
[✓] Checking versions of quarto binary dependencies...
      Pandoc version 3.1.11: OK
      Dart Sass version 1.69.5: OK
      Deno version 1.37.2: OK
[✓] Checking versions of quarto dependencies......OK
[✓] Checking Quarto installation......OK
      Version: 1.4.554
      Path: /Applications/quarto/bin

[✓] Checking tools....................OK
      TinyTeX: v2024.06
      Chromium: (not installed)

[✓] Checking LaTeX....................OK
      Using: TinyTex
      Path: /Users/user/Library/TinyTeX/bin/universal-darwin
      Version: 2024

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

[✓] Checking Python 3 installation....OK
      Version: 3.9.6
      Path: /Users/user/Desktop/home/27_interns/gm_quant_intern_2024/env/bin/python3
      Jupyter: 5.7.2
      Kernels: python3

[✓] Checking Jupyter engine render....OK

[✓] Checking R installation...........OK
      Version: 4.3.2
      Path: /Library/Frameworks/R.framework/Resources
      LibPaths:
        - /Library/Frameworks/R.framework/Versions/4.3-arm64/Resources/library
      knitr: 1.45
      rmarkdown: 2.25

[✓] Checking Knitr engine render......OK

Start by rendering the supplied Quarto document to DOCX and compare the first table cell with the later cells, focusing on the interaction between tbl-subcap and tbl-colwidths. Done means the generated tables retain the requested [80,15,15] widths when subtitles are present, while the existing no-subtitle case remains unchanged.