Dashboard tab orientations are inconsistent in nested tabsets

Bug description

1. orientations are different between different tabsets.
2. cannot set orientation for each tab.

Steps to reproduce

---
title: "Nested tabset"
format: dashboard
---

# Plots

## {.tabset}

### Tabset 1 {orientation="columns"}

#### Plot 1

![Plot 1]({{< placeholder >}})

#### {.tabset}

##### Tabset 1.1

![Plot 1.1]({{< placeholder >}})

##### Tabset 1.2

![Plot 1.2]({{< placeholder >}})

### Tabset 2 {orientation="columns"}

#### Plot 2

![Plot]({{< placeholder >}})

#### {.tabset}

##### Tabset 2.1

![Plot 2.1]({{< placeholder >}})

##### Tabset 2.2

![Plot 2.2]({{< placeholder >}})

Actual behavior

Expected behavior

Same orientation across different tabsets.

Your environment

• IDE: VSCode
• OS: Windows 11

Quarto check output

Quarto 1.6.43
[>] Checking environment information...
      Quarto cache location: C:\Users\Lab\AppData\Local\quarto
[>] Checking versions of quarto binary dependencies...
      Pandoc version 3.4.0: OK
      Dart Sass version 1.70.0: OK
      Deno version 1.46.3: OK
      Typst version 0.11.0: OK
[>] Checking versions of quarto dependencies......OK
[>] Checking Quarto installation......OK
      Version: 1.6.43
      Path: C:\Program Files\Quarto\bin
      CodePage: 1252

[>] Checking tools....................OK
      TinyTeX: (not installed)
      Chromium: (not installed)

[>] Checking LaTeX....................OK
      Tex:  (not detected)

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

[>] Checking Python 3 installation....OK
      Version: 3.10.11
      Path: C:/Users/Lab/AppData/Local/Programs/Python/Python310/python.exe
      Jupyter: 5.7.2
      Kernels: python3

(/) Checking Jupyter engine render....Traceback (most recent call last):
  File "C:\Program Files\Quarto\share\jupyter\jupyter.py", line 21, in <module>
    from notebook import notebook_execute, RestartKernel
  File "C:\Program Files\Quarto\share\jupyter\notebook.py", line 15, in <module>
    from yaml import safe_load as parse_string
ModuleNotFoundError: No module named 'yaml'
[>] Checking Jupyter engine render....OK

Start by rendering the supplied nested-tabset .qmd example with the dashboard format and compare the orientations of the two tabsets. Trace the dashboard tabset rendering entry point to determine how nested orientations and per-tab settings are handled; done means orientations are consistent across tabsets and the expected orientation setting works for each tab.