test: deflake windows metadata ttl expiry assertion (#4050)

The clear-only metadata test used a 1 ms ttl, so on loaded Windows runners set_agent_metadata could see the entry as expired, drop it, and recreate it with a None ttl before next_agent_metadata_expiry() ran. Expiry is forced explicitly later in the test, so use a long ttl to keep the no-extension assertion independent of wall-clock scheduling.

src/terminal/metadata.rs

@@ -861,7 +861,9 @@ mod tests {
             clear_title: false,
             clear_display_agent: false,
             clear_state_labels: false,
-            ttl: Some(Duration::from_millis(1)),
+            // Expiry is forced with the captured deadline below; keep the
+            // no-extension assertion independent of wall-clock scheduling.
+            ttl: Some(Duration::from_secs(60)),
             seq: None,
         });
         let old_deadline = terminal.next_agent_metadata_expiry().unwrap();