Last step of submission needs loading indicator, OJS3

Hi,

When a user submits the manuscript, in the last step when he/she clicks on Finish submission, some time may pass until the submission is processed (maybe due to large figure files, or slow server…), but there is no visible loading indicator to show the user he/she should wait for the confirmation of submission.
This could lead to user leaving the page or clicking back button before the submission is complete. I don’t know if this can cause truncated or otherwise damaged submission.

Thanks,
Faruk