ui: tape/BackupOverview: expand pools by default

normally, users will not have many tape media pools,
and are more interested in the actual media-sets, so
expand those nodes by default

if the list gets very long, the user can collapse some pools anyway

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>

www/tape/BackupOverview.js

@@ -66,6 +66,7 @@ Ext.define('PBS.TapeManagement.BackupOverview', {
 	    for (const [pool, media_sets] of Object.entries(data)) {
 		let pool_entry = Ext.create('Ext.data.TreeModel', {
 		    text: pool,
+		    expanded: true,
 		    leaf: false,
 		});