UI appears stuck when pressing Import/upload button

[mifi]

Initial checklist

• I understand this is a bug report and questions should be posted in the Community Forum
• I searched issues and couldn’t find anything (or linked relevant results below)

Link to runnable example

No response

Steps to reproduce

1. choose Link
2. enter a url
3. Press Import button

originally reported by @kvz

Expected behavior

Some visual feedback like button getting disabled, Ui gets dimmed or a spinner, so that the user understands that something is happening.
Also disabling the button will make sure we don’t get a double action trigger if the user double clicks their mouse (some people have a habit of doing that)

Actual behavior

Nothing happens UI wise when pressing the button, prompting the user to press it again.