I have run the Raspberry install script several times, which has updated to the latest Node-Red but not fixed the issue.
Other Raspberry Pies with the same version of Node-Red show "0 vulnerabilities".
Yes it's the latest version.
I discovered that the problem doesn't arise on the other Pies because the node isn't installed. (Could have sworn it was part of the core)
The big problem with npm audit is that lacks all context.
The "vulnerable" package listed there is minimist. Its a library used to parse command-line arguments.
Working up the stack, we see it is used by poplib - the pop3 client library the email node uses. On further investigation, we see that module includes a couple examples of its use. These examples are run on the command line. node-poplib/demos at master ยท ditesh/node-poplib ยท GitHub
The core of that module - the code that actually gets loaded when you require it - doesn't use minimist.
Thus that vulnerability is completely irrelevant in the context of the Node-RED node.