Set url on switch callback only if it is the current tab

The callback can be triggered when the tab is no more current.
E.g. at the end of a wizard when the screen is reloaded and displayed, the
current record is reset which trigger the callback but the wizard may have
open a new tab meanwhile.

issue8432
review259671002

src/tab.js

@@ -446,7 +446,9 @@
 
             screen.message_callback = this.record_message.bind(this);
             screen.switch_callback = function() {
-                Sao.set_url(this.get_url(), this.name);
+                if (this === Sao.Tab.tabs.get_current()) {
+                    Sao.set_url(this.get_url(), this.name);
+                }
             }.bind(this);
 
             this.set_buttons_sensitive();