editor: Revert flattening of code actions in mouse context menu (#28988)

In light of making context not move dynamically, reverting back these
changes.

- Doing it async will lead to a loading state, which moves the context
menu.
- Doing it sync introduces noticeable lag in opening the context menu.
   
Future idea is to introduce fixed code actions like refactor, rewrite,
etc depending on code action kind [(see
more)](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#codeActionKind)
which will use submenus.
 
Release Notes:

- N/A

crates/editor/src/actions.rs

@@ -99,9 +99,6 @@ pub struct ComposeCompletion {
 pub struct ConfirmCodeAction {
     #[serde(default)]
     pub item_ix: Option<usize>,
-    #[serde(default)]
-    #[serde(skip)]
-    pub from_mouse_context_menu: bool,
 }
 
 #[derive(PartialEq, Clone, Deserialize, Default, JsonSchema)]