Increase border width used to indicate speaking (#4077)

This PR increases the width of the border that we use to indicate when a
call participant is speaking.

This should make it more apparent in the UI when someone is speaking.

Release Notes:

- Increased the width of the ring used to indicate when someone is
speaking in a call.

crates/collab_ui/src/collab_titlebar_item.rs

@@ -486,8 +486,12 @@ impl CollabTitlebarItem {
             .child(
                 Avatar::new(user.avatar_uri.clone())
                     .grayscale(!is_present)
-                    .when(is_speaking, |avatar| {
-                        avatar.border_color(cx.theme().status().info_border)
+                    .border_color(if is_speaking {
+                        cx.theme().status().info_border
+                    } else {
+                        // We draw the border in a transparent color rather to avoid
+                        // the layout shift that would come with adding/removing the border.
+                        gpui::transparent_black()
                     })
                     .when(is_muted, |avatar| {
                         avatar.indicator(