Refactor GitHub Actions workflow to install LaTeX dependencies and build document directly, updating artifact upload step

.github/workflows/main.yml

@@ -22,6 +22,7 @@ jobs:
 
       - name: Install LaTeX
         run: |
+          curl -fsSL https://miktex.org/download/key | sudo tee /usr/share/keyrings/miktex-keyring.asc > /dev/null
           echo "deb [signed-by=/usr/share/keyrings/miktex-keyring.asc] https://miktex.org/download/ubuntu noble universe" | sudo tee /etc/apt/sources.list.d/miktex.list
           apt-get update
           apt-get install miktex