Add-ons Attachment Improvements By Xon 2.7.2

• Fix server error when partial content requests isn't actually possible with the underlying filesystem adaptor

• Fix XF2.3 javascript error when using the "attach" button for non-svg images

• Fix edge case where thumbnails for an svg where not generated as expected
• Fix XF2.3 support
  • Fix XFRM 2.3.x integration failing to save SVG icons.
  • Prevent XF2.3 converting svg attachments/xfrm icons to webp when optimizing images
  • Fix XF2.3 would convert an SVG to PNG client-side on submit
  • Fix svg attachments not generating thumbnail URLs as expected for X2.3