test(suite_onboarding): fix tests for reviewer local machine

- getattr added to get object property 
- detach AUT added in start application attempts
#9284

test/ui-test/src/drivers/SquishDriver.py

@@ -37,6 +37,8 @@ def start_application(app_name: str, attempt = 2):
         toplevelwindow.ToplevelWindow(squish.waitForObject(names.statusDesktop_mainWindow)).maximize()
     except RuntimeError:
         if attempt:
+            time.sleep(1)
+            [ctx.detach() for ctx in squish.applicationContextList()]
             start_application(app_name, attempt-1)
         else:
             raise

test/ui-test/src/drivers/elements/base_element.py

@@ -46,7 +46,7 @@ def is_selected(self) -> bool:
     @property
     def is_visible(self) -> bool:
         try:
-            return squish.waitForObject(self.object_name, 500).visible
+            return getattr(squish.findObject(self.object_name), 'visible', False)
         except LookupError:
             return False