assistant: Unship tool use (#23969)

This PR unships tool use from Assistant1.

This was only ever partially implemented, and was never released to end
users.

Assistant2 will support tool use.

Release Notes:

- N/A

crates/assistant2/src/assistant_panel.rs

@@ -134,7 +134,6 @@ impl AssistantPanel {
                         project,
                         prompt_builder.clone(),
                         slash_commands,
-                        tools.clone(),
                         cx,
                     )
                 })?