fix: improve contrast on homepage credits text (fixes DSpace#5487)

Author: ShivaniNR

src/themes/dspace/app/home-page/home-news/home-news.component.scss

@@ -51,7 +51,8 @@
         color: inherit;
       }
 
-      opacity: 0.3;
+      color: rgba(255, 255, 255, 0.7);
+      background-color: rgba(0, 0, 0, 0.1);
       position: absolute;
       right: var(--bs-spacer);
       bottom: 0;