REPL does not recover from errors

[RichDom2185]

Compare the behaviour of the frontend REPL (running in Source §1, hence no pre-declared list function):

And the CLI REPL (also in Source §1):

Writing any valid program will not work on the CLI REPL as long as it has previously encountered an error, which should not be the case. So far, it seems like the only way to get an output to show is to exit and restart the CLI REPL.

May or may not be related to source-academy/frontend#2596.