Bump!
You can right click on the panel where your tool tray is located and select Manage Widgets.
Then select the status notifier plugin and click the minus (-) sign to disable it.
Note that when I did this it also disabled my ethernet notification and a handy tray icon for Qlipper which was saving a memory of strings saved to the clip board.
Update: After reboot, Qlipper tray icon, and ethernet notification may come back crashing the panel.
A second restart will bring them back with another notification icon, informing that the panel crashed unexpectedly.
It seems to work fine after that. Clearing that crash notification removes the icon, like a good little widget.
So in the end, the above procedure followed by two restarts removed only the two offending update and live patch permanent notification icons in my Lubuntu system (Ubuntu 20.04.2 LTS)