Fix: Only enable search if something is entered (coscine/issues#2015)

src/components/Navbar.vue

@@ -22,7 +22,7 @@
           <b-nav-form @submit.stop.prevent="triggerSearch">
             <b-input-group size="sm" style="width: 25rem">
               <template #prepend>
-                <b-button @click="triggerSearch">
+                <b-button :disabled="!searchTerm" @click="triggerSearch">
                   <b-icon icon="search" />
                 </b-button>
               </template>
@@ -159,8 +159,11 @@ export default defineComponent({
       this.loginStore.logout();
     },
     triggerSearch() {
-      // attach search query, resulting in "/search?q=<searchTerm>"
-      this.$router.push({ name: "search", query: { q: this.searchTerm } });
+      // If searchTerm is not empty
+      if (this.searchTerm) {
+        // attach search query, resulting in "/search?q=<searchTerm>"
+        this.$router.push({ name: "search", query: { q: this.searchTerm } });
+      }
     },
     toggleSidebar() {
       this.mainStore.sidebarActive = !this.mainStore.sidebarActive;