Try removing escaped quotes from bash command in Build Qt workflow

On Windows, the job has started failing with the error:
/usr/bin/bash: "-l": No such file or directory

.github/workflows/build-qt.yml

@@ -157,7 +157,7 @@ jobs:
               run: |
                   $ErrorActionPreference = "Stop"
                   echo "Installing msys packages..."
-                  C:\tools\msys64\usr\bin\bash `"-l`" `"-c`" `"pacman -S --noconfirm make yasm diffutils awk`"
+                  C:\tools\msys64\usr\bin\bash -l -c `"pacman -S --noconfirm make yasm diffutils awk`"
                   echo "Done."
 
             - name: restore ccache