Fix clippy::len_zero lint style violations (#36589)

Related: #36577

Release Notes:

- N/A

---------

Signed-off-by: Umesh Yadav <git@umesh.dev>

crates/agent_servers/src/claude.rs

@@ -1117,7 +1117,7 @@ pub(crate) mod tests {
 
         thread.read_with(cx, |thread, _| {
             entries_len = thread.plan().entries.len();
-            assert!(thread.plan().entries.len() > 0, "Empty plan");
+            assert!(!thread.plan().entries.is_empty(), "Empty plan");
         });
 
         thread