[5.4] Add missing SVG to images extensions

[artur-stepien]

This adds SVG to image extensions list used in \Joomla\CMS\Helper\MediaHelper::isImage. Without this you can select SVG as your banner image but it will not show up in mod_banners

• I read the Generative AI policy and my contribution is either not created with the help of AI or is compatible with the policy and GNU/GPL 2 or later.

Summary of Changes

Treat SVG files as images.

Testing Instructions

• Create a banner with SVG as image.
• Add a mod_banners module to your website and make it display your banners

Actual result BEFORE applying this Pull Request

• A banner with SVG image not showing up

Expected result AFTER applying this Pull Request

• A banner with SVG image showing up

Link to documentations

Please select:

• Documentation link for guide.joomla.org:

• No documentation changes for guide.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed

[chmst]

This was by purpose. https://docs.joomla.org/J4.x:Media:_Uploading_SVG_files

[brianteeman]

beat me to it @chmst

[artur-stepien]

Need to check the reason why my SVG wasn't detected as SVG. As I can see in 5.4-dev branch the mod_banners should checks for image type in two methods. The one I changed and checking mime type.