fix(feature-card-block-large): focus outline now wraps around card pr…

…operly (carbon-design-system#4139)

### Related Ticket(s)

carbon-design-system#3881 

### Description

The previous FeatureCardBlockLarge wasn't focusing correctly due to reusing the `outline` values meant for the `Default` and `Medium` CardBlocks. Inserting custom values to the Large `:focus` state makes it fit more adequately. 

Before (notice bottom right):
![Screen Shot 2020-10-05 at 3 59 55 PM](https://user-images.githubusercontent.com/24970122/95140488-dc86be80-0723-11eb-85ad-952e0dd832ab.png)

After: 
![Screen Shot 2020-10-05 at 3 58 13 PM](https://user-images.githubusercontent.com/24970122/95140401-a77a6c00-0723-11eb-87ea-f3e73aa816ad.png)



### Changelog

**New**

- Added new `outline` values to `.bx--feature-card-block-large .bx--card:focus` 

<!-- React and Web Component deploy previews are enabled by default. -->
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<!-- *** "package: vanilla": Vanilla -->
<!-- *** "package: services": Services -->
<!-- *** "package: utilities": Utilities -->
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packages/styles/scss/components/feature-card-block-large/_feature-card-block-large.scss

@@ -35,6 +35,11 @@ $fcb-breakpoint-up--lg: map-get(
       background: none;
       height: 100%;
 
+      &:focus {
+        outline-width: 3px;
+        outline-offset: 1px;
+      }
+
       @include carbon--breakpoint-between(
         $fcb-large-custom-bp-copy,
         $fcb-breakpoint-up--lg