fix: single instance doesn't shutdown immediately (#1019)

* Fix single instance doesn't shutdown immediately

* Add change file

plugins/single-instance/src/platform_impl/linux.rs

@@ -70,7 +70,8 @@ pub fn init<R: Runtime>(f: Box<SingleInstanceCallback<R>>) -> TauriPlugin<R> {
                             ),
                         );
                     }
-                    std::process::exit(0)
+                    app.cleanup_before_exit();
+                    std::process::exit(0);
                 }
                 _ => {}
             }

plugins/single-instance/src/platform_impl/windows.rs

@@ -62,7 +62,8 @@ pub fn init<R: Runtime>(f: Box<SingleInstanceCallback<R>>) -> TauriPlugin<R> {
                             lpData: bytes.as_ptr() as _,
                         };
                         SendMessageW(hwnd, WM_COPYDATA, 0, &cds as *const _ as _);
-                        app.exit(0);
+                        app.cleanup_before_exit();
+                        std::process::exit(0);
                     }
                 }
             } else {