ui: Improve performance in the CopyButton component (#47292)

This PR improves the performance of the `CopyButton` component by
tracking the copied state locally through a `CopyButtonState` struct
instead of making an OS call every time the component re-renders. Also
pushing a slight improvement here by resetting the state after two
seconds so as to make the check mark go away after you clicked to copy.

Release Notes:

- N/A

crates/git_ui/src/commit_tooltip.rs

@@ -343,7 +343,10 @@ impl Render for CommitTooltip {
                                             ),
                                         )
                                         .child(Divider::vertical())
-                                        .child(CopyButton::new(full_sha).tooltip_label("Copy SHA")),
+                                        .child(
+                                            CopyButton::new("copy-commit-sha", full_sha)
+                                                .tooltip_label("Copy SHA"),
+                                        ),
                                 ),
                         ),
                 )