Reland "Remove cx from ThemeSettings" (#39720)

- **Reapply "Remove cx from ThemeSettings (#38836)" (#39691)**
- **Fix theme loading races**

Closes #ISSUE

Release Notes:

- N/A

crates/editor/src/editor_settings.rs

@@ -176,7 +176,7 @@ impl ScrollbarVisibility for EditorSettings {
 }
 
 impl Settings for EditorSettings {
-    fn from_settings(content: &settings::SettingsContent, _cx: &mut App) -> Self {
+    fn from_settings(content: &settings::SettingsContent) -> Self {
         let editor = content.editor.clone();
         let scrollbar = editor.scrollbar.unwrap();
         let minimap = editor.minimap.unwrap();