workspace-indicator: Minor cleanup

Pass the style class at construction time instead of setting it later.

https://gitlab.gnome.org/GNOME/gnome-shell-extensions/merge_requests/71

extensions/workspace-indicator/extension.js

@@ -23,6 +23,7 @@ class WorkspaceIndicator extends PanelMenu.Button {
 
         this._currentWorkspace = workspaceManager.get_active_workspace_index();
         this._statusLabel = new St.Label({
+            style_class: 'panel-workspace-indicator',
             y_align: Clutter.ActorAlign.CENTER,
             text: this._labelText()
         });
@@ -43,9 +44,6 @@ class WorkspaceIndicator extends PanelMenu.Button {
         this.connect('scroll-event', this._onScrollEvent.bind(this));
         this._createWorkspacesSection();
 
-        //styling
-        this._statusLabel.add_style_class_name('panel-workspace-indicator');
-
         this._settings = new Gio.Settings({ schema_id: WORKSPACE_SCHEMA });
         this._settingsChangedId = this._settings.connect(
             `changed::${WORKSPACE_KEY}`,