edit predictions: Cache settings across renders (#24581)

We were reading edit prediction settings too often, causing frames to be
dropped. We'll now cache them and update them from
`update_visible_inline_completion`.

Release Notes:

- N/A

crates/zeta/src/rate_completion_modal.rs

@@ -279,7 +279,7 @@ impl RateCompletionModal {
                 editor.set_show_runnables(false, cx);
                 editor.set_show_wrap_guides(false, cx);
                 editor.set_show_indent_guides(false, cx);
-                editor.set_show_inline_completions(Some(false), window, cx);
+                editor.set_show_edit_predictions(Some(false), window, cx);
                 editor.set_placeholder_text("Add your feedback…", cx);
                 if focus {
                     cx.focus_self(window);