Fix to Mobile navbar hamburger menu for base (custom) theme

DSpace#2444 only fixes the DSpace theme, not the base (and custom) theme.

Author: eulereadgbe

src/app/navbar/navbar.component.scss

@@ -10,7 +10,7 @@
   /** Mobile menu styling **/
   @media screen and (max-width: map-get($grid-breakpoints, md)-0.02) {
     .navbar {
-      width: 100%;
+      width: 100vw;
       background-color: var(--bs-white);
       position: absolute;
       overflow: hidden;