fix: fix link.

Author: DvdBr3o

src/components/Yatcc/YatccTopbar.astro

@@ -13,7 +13,7 @@ const translatePath = useTranslatedPath(lang);
 <div>
   <Topbar logoText="YatCC AI">
     <Fragment slot="nav-items">
-      <Link href="https://ol.yatcc.arcsysu.cn/" target="_blank">&#128640; 进入平台</Link>
+      <Link href="https://ol.yatcc.arcsysu.cn/">&#128640; 进入平台</Link>
       <div class="nav-dropdown-item nav-dropdown-impl">
         <NavDropdown>
           <div slot="title">{t("nav.implementation")}</div>