Stop showing diagnostics in the diff-related editors (#33285)

<img width="1728" alt="image"
src="https://github.com/user-attachments/assets/a63925a7-8e13-4d48-bd31-33f434209ea6"
/>

Diagnostics UI elements (underlines, popovers, hovers) are quite noisy
by themselves and get even more so with the git background colors.

Release Notes:

- Stopped showing diagnostics in the diff-related editors

crates/git_ui/src/diff_view.rs

@@ -94,7 +94,7 @@ impl DiffView {
             let mut editor =
                 Editor::for_multibuffer(multibuffer.clone(), Some(project.clone()), window, cx);
             editor.start_temporary_diff_override();
-            editor.disable_inline_diagnostics();
+            editor.disable_diagnostics(cx);
             editor.set_expand_all_diff_hunks(cx);
             editor.set_render_diff_hunk_controls(
                 Arc::new(|_, _, _, _, _, _, _, _| gpui::Empty.into_any_element()),

crates/git_ui/src/project_diff.rs

@@ -141,7 +141,7 @@ impl ProjectDiff {
         let editor = cx.new(|cx| {
             let mut diff_display_editor =
                 Editor::for_multibuffer(multibuffer.clone(), Some(project.clone()), window, cx);
-            diff_display_editor.disable_inline_diagnostics();
+            diff_display_editor.disable_diagnostics(cx);
             diff_display_editor.set_expand_all_diff_hunks(cx);
             diff_display_editor.register_addon(GitPanelAddon {
                 workspace: workspace.downgrade(),