Allow deselecting chosen file during video upload

[KemalKrKX]

Is your feature request related to a problem? Please describe.
When testing the video upload feature I realized there is no way to cancel uploading a file once it is selected other than exiting the whole process and beginning anew. It would be a nice upgrade to allow changing the selected file to no file selected.

Describe the solution you'd like
A cancel selection button on either in the admin interface or in the file selection prompt.