[PLAY-3185] Add Kit Category SVGs for Container and Full Screen (#6553)

**What does this PR do?** A clear and concise description with your
runway ticket url.
[PLAY-3185](https://runway.powerhrg.com/backlog_items/PLAY-3185) adds
kit category svgs for our two newest kits, Full Screen and Container,
which can be seen on the Layout & Structure kit category page.

**Screenshots:** Screenshots to visualize your addition/change
<img width="1714" height="1022" alt="PLAY3185side by side"
src="https://github.com/user-attachments/assets/861cb426-cbc3-4496-a904-218a20a59c64"
/>


**How to test?** Steps to confirm the desired behavior:
1. Go to the Layout & Structure Kit Category page in prod vs. review env
to see the Container and Full Screen Kit Cards without, then with, kit
svgs.


#### Checklist:
- [x] **LABELS** Add a label: `enhancement`, `bug`, `improvement`, `new
kit`, `deprecated`, or `breaking`. See [Changelog &
Labels](https://github.com/powerhome/playbook/wiki/Changelog-&-Labels)
for details.
- [x] **DEPLOY** I have added the `milano` label to show I'm ready for a
review.
~~- [ ] **TESTS** I have added test coverage to my code.~~
~~- [ ] **PLAYGROUND** I have added and tested Playground metadata and
overrides for all kits and props updated in my code.~~
- [x] **SEMVER** I have added a `minor`, `major`, or `patch` label for
release.
- [x] **RC** I have added an `inactive RC` label if not an active RC.

Author: ElisaShapiro

playbook-website/app/javascript/images/kit_previews/layout_and_structure/container.svg

@@ -1,8 +1,10 @@
 import background from "./background.svg";
 import card from "./card.svg";
 import collapsible from "./collapsible.svg";
+import container from "./container.svg";
 import draggable from "./draggable.svg";
 import flex from "./flex.svg";
+import fullScreen from "./full_screen.svg";
 import layout from "./layout.svg";
 import overlay from "./overlay.svg";
 import sectionSeparator from "./section_sesparator.svg";
@@ -11,8 +13,10 @@ export const layoutAndStructurePreviewMap = {
   "layout_and_structure/background": background,
   "layout_and_structure/card": card,
   "layout_and_structure/collapsible": collapsible,
+  "layout_and_structure/container": container,
   "layout_and_structure/draggable": draggable,
   "layout_and_structure/flex": flex,
+  "layout_and_structure/full_screen": fullScreen,
   "layout_and_structure/layout": layout,
   "layout_and_structure/overlay": overlay,
   "layout_and_structure/section_separator": sectionSeparator,