Fix missed renames in #22632 (#23688)

Fix a bug where a GPUI macro still used `ModelContext`
Rename `AsyncAppContext` -> `AsyncApp`
Rename update_model, read_model, insert_model, and reserve_model to
update_entity, read_entity, insert_entity, and reserve_entity

Release Notes:

- N/A

crates/vim/src/normal/repeat.rs

@@ -349,7 +349,7 @@ mod test {
     use futures::StreamExt;
     use indoc::indoc;
 
-    use gpui::ViewInputHandler;
+    use gpui::EntityInputHandler;
 
     use crate::{
         state::Mode,

crates/vim/src/normal/search.rs

@@ -573,6 +573,7 @@ mod test {
     };
     use editor::EditorSettings;
     use editor::{display_map::DisplayRow, DisplayPoint};
+
     use indoc::indoc;
     use search::BufferSearchBar;
     use settings::SettingsStore;
@@ -669,7 +670,7 @@ mod test {
                 .expect("Buffer search bar should be deployed")
         });
 
-        cx.update_model(search_bar, |bar, _window, cx| {
+        cx.update_entity(search_bar, |bar, _window, cx| {
             assert_eq!(bar.query(cx), "cc");
         });