[REG: 5.7.1 -> 5.8.0]: <input type="file"> does not work in Qt Web Engine

The component <input type="file"> does not work in the QtWebEngine. Clicking the button created by this html tag properly opens usable open file dialog, but selecting a file from there does not show up after the open file dialog is closed. Furthermore, if you select a file once, the browse for file button no longer works until page refresh.

Steps to reproduce:

• Run Demo Browser example
• Navigate to "https://www.w3schools.com/jsref/tryit.asp?filename=tryjsref_fileupload_get"
• Click the "Browse..." button
• Choose a file
• EXPECTED: File is chosen and the file name is shown next to the "Browse..." button
• ACTUAL: File is not chosen and the button is disabled for further use