include-before-body does not preserve key order when using both text and file

Bug description

include-before-body does not preserve order of keys when both text and file keys are used. Similarly unexpected behavior occurs with include-after-body and include-in-header as well.

Steps to reproduce

example.qmd

---
include-before-body:
- text: a man
- file: _aplan.md
- text: a canal panama
format: 
  html: default
  pdf: default
---

> The above text should read "a man a plan a canal panama", but the order of the `include-before-body` keys is not preserved.

_aplan.md

a plan 

Expected behavior

I expect the order of include keys to be preserved so that the output would read

a man a plan a canal panama

Actual behavior

It appears that the keys are sorted before inclusion, so that file contents are included before text contents. I would expect that the order of keys is preserved for includes. This results in the out of order output:

a plan a man a canal panama

Your environment

• OS: macOS Sonoma 14.2.1

Quarto check output

[✓] Checking versions of quarto binary dependencies...
      Pandoc version 3.1.1: OK
      Dart Sass version 1.55.0: OK
[✓] Checking versions of quarto dependencies......OK
[✓] Checking Quarto installation......OK
      Version: 1.3.450
      Path: /Applications/quarto/bin

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

[✓] Checking Python 3 installation....OK
      Version: 3.11.6
      Path: /opt/homebrew/opt/python@3.11/bin/python3.11
      Jupyter: 5.3.0
      Kernels: python3

(/) Checking Jupyter engine render....0.00s - Debugger warning: It seems that frozen modules are being used, which may
0.00s - make the debugger miss breakpoints. Please pass -Xfrozen_modules=off
0.00s - to python to disable frozen modules.
0.00s - Note: Debugging will proceed. Set PYDEVD_DISABLE_FILE_VALIDATION=1 to disable this validation.
0.00s - Debugger warning: It seems that frozen modules are being used, which may
0.00s - make the debugger miss breakpoints. Please pass -Xfrozen_modules=off
0.00s - to python to disable frozen modules.
0.00s - Note: Debugging will proceed. Set PYDEVD_DISABLE_FILE_VALIDATION=1 to disable this validation.
[✓] 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: 1.44
      rmarkdown: 2.25

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

Reproduce the behavior with example.qmd and _aplan.md, checking include-before-body first and then the analogous include-after-body and include-in-header cases. Trace the include handling from the CLI entry point, and consider the work complete when mixed text and file entries retain their declared order in the rendered output.