Disable install button during extension installation

[atirut-w]

Is your feature request related to a problem? Please describe.
If an extension takes a little too long to download, the user (read: I/me) can become confused and might try to press the install button again, which can cause some weirdness to happen. This happened to me with GSConnect and it caused the GSConnect tray to duplicate.

Describe the solution you'd like
Either simply disable the install button on an extension in the middle of download and/or install, or show a download and install progress

Additional context
Add any other context or screenshots about the feature request here.

[oscfdezdz]

Hi, thanks for reporting the issue, probably the best option in this case is to disable the button while the extension is being downloaded or installed as the extensions only take up a few kilobytes and a progress bar would be instant in the vast majority of cases.