fix(card-section-carousel): fixes horizontal scroll (#5042)

### Related Ticket(s)

#4781 

### Description

For Card Section Carousel, on 300% zoom you need to scroll both horizontally and vertically to see the full page contents. This fix gets rid of the horizontal scroll, bringing accessibility back in check. This will also fix horizontal scroll on all other web components that use Content Section

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packages/web-components/src/components/content-section/content-section.scss

@@ -1,5 +1,5 @@
 //
-// Copyright IBM Corp. 2020
+// Copyright IBM Corp. 2020, 2021
 //
 // This source code is licensed under the Apache-2.0 license found in the
 // LICENSE file in the root directory of this source tree.
@@ -12,4 +12,5 @@
 :host(#{$dds-prefix}-content-section-heading),
 :host(#{$dds-prefix}-content-section-copy) {
   display: block;
+  overflow-x: hidden;
 }