ISTWCMS-7227: add focus state for cookie banner button

src/patterns/04-components/eu-cookie-compliance/_eu-cookie-compliance.scss

@@ -65,7 +65,8 @@
     font-weight: var(--font-weight-400);
     line-height: 1.25;
 
-    &:hover {
+    &:hover,
+    &:focus {
       background-color: transparent;
       border: 2px solid var(--uw-black);
       color: var(--uw-black);