Add support for button loader on final step when clicking the OK button

[anuj-kumary]

I am using your package and noticed that there is no support for showing a button loader when clicking the OK button on the final step of a process. This feature is essential for better UX, as it indicates to the user that their action is being processed.

Expected Behavior: When a user clicks the OK button on the final step, the button should display a loader until the process is complete.

Current Behavior: Currently, there is no support for showing a loader on the OK button in the final step.

Use Case: This feature is important when there is a time-consuming process after clicking the OK button so that users can have visual feedback.