loginDialog: Do not expand "Not listed" button

Visually the button is just an interactive label, so having the
interactive area extend to the empty space next to the label
is surprising.

Instead, left-align the whole button rather than just the label
inside, so the clickable area corresponds to the visible one.

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/1046

js/gdm/loginDialog.js

@@ -456,7 +456,6 @@ var LoginDialog = GObject.registerClass({
         let notListedLabel = new St.Label({
             text: _("Not listed?"),
             style_class: 'login-dialog-not-listed-label',
-            x_align: Clutter.ActorAlign.START,
         });
         this._notListedButton = new St.Button({
             style_class: 'login-dialog-not-listed-button',
@@ -464,6 +463,7 @@ var LoginDialog = GObject.registerClass({
             can_focus: true,
             child: notListedLabel,
             reactive: true,
+            x_align: Clutter.ActorAlign.START,
         });
 
         this._notListedButton.connect('clicked', this._hideUserListAskForUsernameAndBeginVerification.bind(this));