[BUG] Disable auto fetch from server repository feature not working

[sapphirepro]

Describe the bug
Disable auto fetch from server repository feature not working.

To Reproduce
Open any existing repo with default settings, where auto fetch enabled. Then try to go to settings of repo and try to set auto fetch to 0 (there is written, that 0 = disabled). It doesn't let you set value below 1. So even feature promoted, in fact it doesn't work, as setting zerro from GUI is impossible.

Expected behavior
Should allow to set auto fetch time to 0 and actually disable any automated repo fetching from server and leave it to user to do that manually.

Screenshots
Attached.

Desktop (please complete the following information):

• OS: OpenSuse Tumbleweed
• Release version or SHA: 1.5.0

Additional context
Add any other context about the problem here.