js: Use templates for non-translatable strings

This reverts commit 9d941f8202 and replaces all additional
instances of .format() that have been added since.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2160>

js/ui/overview.js

@@ -390,7 +390,7 @@ var Overview = class {
             this._shown = false;
             this._visibleTarget = false;
             this.emit('hiding');
-            Main.panel.style = 'transition-duration: %dms;'.format(duration);
+            Main.panel.style = `transition-duration: ${duration}ms;`;
             onComplete = () => this._hideDone();
         } else {
             onComplete = () => this._showDone();