zed: Reduce clones (#30550)

A collection of small patches that reduce clones. Mostly by using owned
iterators where possible.

Release Notes:

- N/A

crates/agent/src/thread.rs

@@ -2241,7 +2241,7 @@ impl Thread {
             .read(cx)
             .enabled_tools(cx)
             .iter()
-            .map(|tool| tool.name().to_string())
+            .map(|tool| tool.name())
             .collect();
 
         self.message_feedback.insert(message_id, feedback);