Change "No update available" text when update-check is disabled

[skst]

Please describe.
When the update feature is disabled, SoundSwitch's context menu says, "No update available." This is a bit misleading because SoundSwitch does not actually know if an update is available or not.

Describe the solution you'd like
Perhaps change the "No update available" text to something that indicates updates are not, in fact, being checked, such as, "Check for updates disabled."

Describe alternatives you've considered
Or perhaps remove the menu entry altogether if SoundSwitch is not checking for updates.

Additional context