Allow UI font weight to be assigned in settings (#12333)

Release Notes:

- Added the ability to configure the weight of your UI font in standard
CSS weight units from 0 to 900.

crates/collab_ui/src/chat_panel/message_editor.rs

@@ -524,7 +524,7 @@ impl Render for MessageEditor {
             font_family: settings.ui_font.family.clone(),
             font_features: settings.ui_font.features.clone(),
             font_size: TextSize::Small.rems(cx).into(),
-            font_weight: FontWeight::NORMAL,
+            font_weight: settings.ui_font.weight,
             font_style: FontStyle::Normal,
             line_height: relative(1.3),
             background_color: None,