Fix content list error when projects is undefined (#3026)

Co-authored-by: Geometrically <18202329+Geometrically@users.noreply.github.com>

apps/app-frontend/src/pages/instance/Mods.vue

@@ -1,5 +1,5 @@
 <template>
-  <template v-if="projects.length > 0">
+  <template v-if="projects?.length > 0">
     <div class="flex items-center gap-2 mb-4">
       <div class="iconified-input flex-grow">
         <SearchIcon />