Ddpadil, Thank you so much for your response. I figured it out what was the problem.
I will explain here for other team members:
This is the problem of Selector.
I have taken selector with out aaname=File name.
because of this UiPath is always able to enter the full file path but chrome browser is considering default name as file.
hope this info is useful.
Thanks to all who tried to help me on this topic