assistant2: Improve Lua script rendering (#26389)

This PR improves the rendering of Lua scripts provided to the scripting
tool.

We now render them in code blocks with syntax highlighting:

<img width="1297" alt="Screenshot 2025-03-10 at 2 40 51 PM"
src="https://github.com/user-attachments/assets/def65b5c-86a8-490f-aaa5-5cc1687fe01e"
/>

Release Notes:

- N/A

crates/scripting_tool/src/scripting_tool.rs

@@ -8,8 +8,8 @@ use schemars::JsonSchema;
 use serde::Deserialize;
 
 #[derive(Debug, Deserialize, JsonSchema)]
-struct ScriptingToolInput {
-    lua_script: String,
+pub struct ScriptingToolInput {
+    pub lua_script: String,
 }
 
 pub struct ScriptingTool;