#2745 - handle non-displayable images

What is in this MR

• use WebP format for thumbnails
• minor code improvements for closable objects in thumbnails generation command

What's missing:

• Such images will not be displayed properly in preview overlay: #2745 (comment 1969125188)

How to test this MR

• Create file field
• upload PSD or TIFF file.
• observe thumbnails

Merge Request Checklist

• A changelog entry has been created if required.
• New/updated Premium/Enterprise features are separated correctly in the premium or enterprise folder
• The latest Chrome and Firefox have been used to test any new frontend features
• Documentation has been updated
• Quality Standards are met
• Performance: tables are still fast with 100k+ rows, 100+ field tables
• The redoc API pages have been updated for any REST API changes
• Our custom API docs are updated for changes to endpoints accessed via api tokens
• The UI/UX has been updated following UI Style Guide