Fix error when exec is disabled

[MrMusic]

This is a fix for issue https://github.com/JoomGalleryfriends/JG4-dev/issues/221 If the 'exec' function is deactivated on the server, an error occurs when the JoomGallery configuration is opened.

How to test this PR

Add 'exec' to the list of disabled functions in php.ini: disable_functions="show_source, system, shell_exec, exec"

Test result before applying this PR

A PHP error occurs when opening the JoomGallery configuration.

Test result after applying this PR

No error is thrown.

[eumel1602]

PR getestet funktioniert! J4.4.4 (PHP 8.1 und 8.2)

[rowi68]

I have tested this PR ✅ successfully. ( J 5.0.3 / PHP 8.2 )

[MrMusic]

Thanks for testing!

[Elfangor93]

Thank you very much.