Bug 514044

SUMMARY
When using the %body argument to an external script, the %body argument is always empty instead of containing the body/contents of the selected mail on which the external script is run. I have tried both HTML and plaintext mails.   

STEPS TO REPRODUCE
0. Create a script that allows you to see the %body argument, for example:
```
#!/bin/bash
kdialog --passivepopup "$1" 10
``` 
1. Go to `Settings`->`Configure KMail`->`Plugins` 
2. Enable the 'External Script' plugin (checkbox) and click the configure button
3. Click Add Script
4. Fill in a name and for Executable pick your script
5. Add %body in the argument field (just %body without quotes)
6. Click OK and apply the changes
7. Right click on a message -> External Script -> Name you gave the script

OBSERVED RESULT
The kdialog pop up appears, but is empty. 
Using #1 in the script shows that there is an argument (number of arguments = 1), but apparently it filled with an empty string?
Other values such as %s and %from work as expected.

EXPECTED RESULT
The %body argument should not be empty => the KDialog pop up window should show the body/content of the selected mail.

SOFTWARE/OS VERSIONS
KDE Plasma Version:  6.5.4
KDE Frameworks Version: 6.21.0
Qt Version: 6.10.1

ADDITIONAL INFORMATION