How can I hide the "An error occurred" tray indicator icon?

What steps are required for the following tray indicator icon to disappear? Alternatively, is it possible to hide this icon manually?

The best and recommended way to make the error notification icon disappear is to resolve the root cause. The message shown in the screenshot above notifies you about a serious problem with the software sources. It seems that you are having unmet dependencies.

To solve this issue execute sudo apt install -f. If you still receive this special error message, investigate the software sources by checking the /etc/apt/sources.list file and the files in the etc/apt/sources.list.d folder for wrong entries and correct them.

When you execute sudo apt update afterwards, this error notification icon will be gone and that's the way you should go. Removing the icon manually would not be the solution you want, operating system security and stability is more important than optical things.