[Feature Request] Add Time of last check to Updates

[AndrewLuecke]

Overview:
At the moment, the updates section only reports "All Installed Applications are up to date". It would however be good if it reported when it was last checked too

This is useful when the window is left open, or is opened, to ensure you know if the update info is up to date

Current Results:
Currently Shows "All Installed Applications are up to date" when all updates are installed

Expected
Should show "All Installed Applications are Up to Date. Last checked at 12:23AM on 25/12/2025)

[iamkartiknayak]

Also it needs to stop looking for updates everytime the Updates is selected in navbar.