allow abstract-title in yaml front matter for latex pdf output

Bug description

When setting the abstract-title keyword in the front matter yaml, the abstract title is not actually changed in pdf output.

There is a work-around, which is redefine the name in the latex header using:

format: 
    pdf:
        documentclass: article
        include-in-header:
            text: |
                \renewcommand{\abstractname}{Executive Summary}

Steps to reproduce

Rendering the following quarto document creates a pdf with the abstract title set to "Abstract"

---
title: "quarto-abstract"
abstract: "Read the executive summary."
abstract-title: "Executive summary"
format: 
    pdf:
        documentclass: article
---

## Quarto

Quarto enables you to weave together content and executable code into a finished document. To learn more about Quarto see <https://quarto.org>.

Expected behavior

The abstract title would be set to the keyword value in the front matter yaml, in this case "Executive Summary".

Actual behavior

The abstract title is set to "Abstract"

Your environment

• Ubuntu 20.04
• emacs as text editor

Quarto check output

$ quarto check

[✓] 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: 1.3.433
      Path: /opt/quarto/bin

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

[✓] Checking Python 3 installation....OK
      Version: 3.8.3
      Path: /home/apn/sw/bin/python3
      Jupyter: 4.10.0
      Kernels: julia-1.8, python3

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

[✓] Checking R installation...........OK
      Version: 4.3.0
      Path: /usr/lib/R
      LibPaths:
        - /usr/local/lib/R/site-library
        - /usr/lib/R/site-library
        - /usr/lib/R/library
      knitr: (None)
      rmarkdown: (None)

      The rmarkdown package is not available in this R installation.
      Install with install.packages("rmarkdown")

Start by reproducing the issue with the provided Quarto document and PDF format settings, then trace how the YAML abstract-title value is passed into LaTeX PDF output. Done means the rendered PDF uses the front matter value, such as "Executive summary", instead of the default "Abstract".