Use small labels for title bar buttons (#3763)

This PR adjusts the sizing of the labels in the buttons in the title bar
to use the small label size.

This should bring them more in line with how things looked in Zed1.

Release Notes:

- N/A

crates/collab_ui2/src/collab_titlebar_item.rs

@@ -334,6 +334,7 @@ impl CollabTitlebarItem {
             .trigger(
                 Button::new("project_name_trigger", name)
                     .style(ButtonStyle::Subtle)
+                    .label_size(LabelSize::Small)
                     .tooltip(move |cx| Tooltip::text("Recent Projects", cx))
                     .on_click(cx.listener(|this, _, cx| {
                         this.toggle_project_menu(&ToggleProjectMenu, cx);
@@ -368,6 +369,7 @@ impl CollabTitlebarItem {
                     Button::new("project_branch_trigger", branch_name)
                         .color(Color::Muted)
                         .style(ButtonStyle::Subtle)
+                        .label_size(LabelSize::Small)
                         .tooltip(move |cx| {
                             Tooltip::with_meta(
                                 "Recent Branches",