fix: export card components from index

Signed-off-by: Sofia Sjöblad <ssjoblad@spotify.com>

.changeset/curly-memes-roll.md

@@ -0,0 +1,5 @@
+---
+'@backstage/ui': patch
+---
+
+Export CardHeader, CardBody and CardFooter from Card component index

packages/ui/src/components/Card/index.ts

@@ -14,7 +14,8 @@
  * limitations under the License.
  */
 
-export { Card } from './Card';
+export { Card, CardHeader, CardBody, CardFooter } from './Card';
+
 export type {
   CardProps,
   CardHeaderProps,