left_sidebar: Fix click handler selector for all private messages.

The previous logic did not correctly handle clicks that were in the
tiny spaces inside the link tag but outside the icon element.

Fixes #25647.

web/src/click_handlers.js

@@ -719,7 +719,7 @@ export function initialize() {
         "click",
         ".private_messages_container.zoom-out #private_messages_section_header",
         (e) => {
-            if (e.target.classList.value === "fa fa-align-right") {
+            if ($(e.target).closest("#show_all_private_messages").length === 1) {
                 // Let the browser handle the "all direct messages" widget.
                 return;
             }