bug: unable to cancel download on progress bar while backend is downloading

[Minh141120]

Describe the Bug

On Windows, when the backend is downloading, I try to cancel the download but seems not working and the dev console said Error cancelling download: No download task....

Steps to Reproduce

1. Install v0.6.7
2. Try to switch to old backend version (b5857 cuda)
3. Click "x" on the progress bar

Screenshots / Logs

Propose Solution

• We need to hide the progress bar
• If we are offline, we need to show a popup that the backend is not available, need to go online for setup

Operating System

• MacOS
• Windows
• Linux