Don't show announcement banner if html is empty

Author: melissawm

src/pydata_sphinx_theme/theme/pydata_sphinx_theme/sections/announcement.html

@@ -7,9 +7,14 @@
 fetch("{{ theme_announcement }}")
   .then(res => {return res.text();})
   .then(data => {
-    div = document.querySelector(".bd-header-announcement");
-    div.classList.add(...{{ header_classes | tojson }});
-    div.innerHTML = `<div class="bd-header-announcement__content">${data}</div>`;
+    if (data.length === 0) {
+      console.log("[PST]: Empty announcement at: {{ theme_announcement }}");
+      return;
+    } else {
+      div = document.querySelector(".bd-header-announcement");
+      div.classList.add(...["bd-header-announcement", "container-fluid"]);
+      div.innerHTML = `<div class="bd-header-announcement__content">${data}</div>`;
+    }
   })
   .catch(error => {
     console.log("[PST]: Failed to load announcement at: {{ theme_announcement }}");