Handle duplicate files uploaded through filepicker

Hello testers This issue needs to test in html editor and file manager. HTML Editor 1. Adding a picture to html editor with name for example: test.jpg 2. Adding another picture with the same name by using upload/local/recent/private repository plugins, you should see a dialog pop up asking you want to overwrite/rename or cancel, try all options to see if it works as expected. File manager, for example in your private file management page 1. Adding a picture to filemanager with name for example: test.jpg 2. Adding another picture with the same name using upload/local/recent/private repository plugins, you should see a dialog pop up asking you want to overwrite/rename or cancel, try all options to see if it works as expected.