Rework the contact panel's styling to allow keyboard navigation

Co-authored-by: Nathan Sobo <nathan@zed.dev>

crates/theme/src/theme.rs

@@ -246,9 +246,15 @@ pub struct ContactsPanel {
     pub contact_avatar: ImageStyle,
     pub contact_username: ContainedText,
     pub contact_button: Interactive<IconButton>,
+    pub contact_button_spacing: f32,
     pub disabled_contact_button: IconButton,
-    pub tree_branch_width: f32,
-    pub tree_branch_color: Color,
+    pub tree_branch: Interactive<TreeBranch>,
+}
+
+#[derive(Deserialize, Default, Clone, Copy)]
+pub struct TreeBranch {
+    pub width: f32,
+    pub color: Color,
 }
 
 #[derive(Deserialize, Default)]
@@ -273,8 +279,8 @@ pub struct IconButton {
 pub struct ProjectRow {
     #[serde(flatten)]
     pub container: ContainerStyle,
-    pub height: f32,
     pub name: ContainedText,
+    pub guests: ContainerStyle,
     pub guest_avatar: ImageStyle,
     pub guest_avatar_spacing: f32,
 }