feat(card): Add shape feature to card and style into Ionic theme (#29292)

Issue number: resolves #

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## What is the new behavior?
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- Adds the new shapes to ionic theme card

## Does this introduce a breaking change?

- [ ] Yes
- [X] No

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Co-authored-by: Brandy Carney <brandy@ionic.io>

core/src/foundations/ionic.root.scss

@@ -17,6 +17,7 @@
   --ionic-color-primary-900: #010408;
   --ionic-color-primary: #1068eb;
   --ionic-color-secondary: #303d60;
+  --ionic-color-neutral-0: #ffffff;
   --ionic-color-neutral-10: #f5f5f5;
   --ionic-color-neutral-50: #e7e7e7;
   --ionic-color-neutral-100: #dadada;