[Feature] Add support for fallback images for the Figure Twig template

[titouanmathis]

🔗 Linked issue

❓ Type of change

• 📖 Documentation (updates to the documentation, readme or JSdoc annotations)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

📝 Checklist

• I have linked an issue or discussion.
• I have added tests (if possible).
• I have updated the documentation accordingly.
• I have updated the changelog.

[github-actions]

Export Size

Unchanged

@studiometa/ui

Name	Size	Diff
AbstractPrefetch	411 B	-
AbstractScrollAnimation	461 B	-
AbstractSliderChild	2.46 kB	-
Accordion	1.06 kB	-
AccordionItem	1.02 kB	-
Action	508 B	-
ALL	11.91 kB	-
AnchorNav	615 B	-
AnchorNavLink	480 B	-
AnchorNavTarget	207 B	-
AnchorScrollTo	243 B	-
animationScrollWithEase	272 B	-
ATOMS	4.3 kB	-
CircularMarquee	339 B	-
Cursor	665 B	-
Draggable	327 B	-
Figure	694 B	-
FigureTwicpics	1.15 kB	-
FigureVideo	983 B	-
FigureVideoTwicpics	1.48 kB	-
Frame	1.68 kB	-
FrameAnchor	201 B	-
FrameForm	198 B	-
FrameTarget	777 B	-
LargeText	492 B	-
LazyInclude	418 B	-
loadImage	694 B	-
Menu	1.38 kB	-
MenuBtn	230 B	-
MenuList	943 B	-
Modal	908 B	-
ModalWithTransition	1.02 kB	-
MOLECULES	7.12 kB	-
ORGANISMS	1.74 kB	-
Panel	1.26 kB	-
PrefetchWhenOver	468 B	-
PrefetchWhenVisible	480 B	-
PRIMITIVES	632 B	-
ScrollAnimation	513 B	-
ScrollAnimationChild	650 B	-
ScrollAnimationChildWithEase	851 B	-
ScrollAnimationParent	712 B	-
ScrollAnimationWithEase	711 B	-
ScrollReveal	622 B	-
Sentinel	217 B	-
Slider	2.26 kB	-
SliderBtn	2.62 kB	-
SliderCount	2.49 kB	-
SliderDots	2.7 kB	-
SliderDrag	353 B	-
SliderItem	733 B	-
SliderProgress	2.54 kB	-
Sticky	859 B	-
TableOfContent	742 B	-
TableOfContentAnchor	550 B	-
Tabs	625 B	-
Transition	387 B	-