feat(card): update heading and description spacing (#13320)

**Related Issue:**
[#12304](#12304)

## Summary

Remove `margin-top` from `description` slot.
Update `heading` and `description` line heights to
`--calcite-font-line-height-relative-snug`.

Author: aPreciado88

packages/components/src/components/card/card.scss

@@ -117,13 +117,15 @@
     text-n1-wrap
     m-0
     font-medium;
+  line-height: var(--calcite-font-line-height-relative-snug);
 }
 
 @include includes.slotted("description", "*") {
   @apply text-color-2
     text-n2-wrap
-    m-0 mt-0.5
+    m-0
     font-normal;
+  line-height: var(--calcite-font-line-height-relative-snug);
 }
 
 @include includes.slotted("thumbnail", "img") {