Joint drive test: wait as long as the other preview tests (#1549) (#1582)

Thanks @DuBearte.

crates/ui-egui/src/dialogs_assembly_tests.rs

@@ -363,7 +363,9 @@ fn drive_slider_previews_intermediate_positions_before_release() {
     let second = preview_commands(&h.app, h.app.dialog.as_ref().unwrap()).unwrap();
     assert_ne!(first, second, "the held slider requests a new pose before release");
     assert!(h.ctx.input(|i| i.pointer.primary_down()));
-    let deadline = std::time::Instant::now() + std::time::Duration::from_secs(10);
+    // The preview runs on a worker thread; on a machine busy with other test binaries it can
+    // take several seconds, so wait as long as the other preview tests do (#1549).
+    let deadline = std::time::Instant::now() + std::time::Duration::from_secs(60);
     while h.app.preview.busy {
         assert!(std::time::Instant::now() < deadline, "held-slider preview did not finish");
         std::thread::sleep(std::time::Duration::from_millis(1));