fix: update skip nav destination (#1516)

src/tab-page/LoadedTabPage.jsx

@@ -69,7 +69,7 @@ const LoadedTabPage = ({
         streakDiscountCouponEnabled={streakDiscountCouponEnabled}
         verifiedMode={verifiedMode}
       />
-      <main id="main-content" className="d-flex flex-column flex-grow-1">
+      <main className="d-flex flex-column flex-grow-1">
         <AlertList
           topic="outline"
           className="mx-5 mt-3"
@@ -79,7 +79,7 @@ const LoadedTabPage = ({
           }}
         />
         <CourseTabsNavigation tabs={tabs} className="mb-3" activeTabSlug={activeTabSlug} />
-        <div className="container-xl">
+        <div id="main-content" className="container-xl">
           {children}
         </div>
       </main>