fix: log error message when external JS fails to load

[Boris-c]

Change log level of external extension error stack from debug to error.

-> Makes it easier to debug.
-> Makes it easier for end users to report the stack when filing a bug report.

[Nerivec]

Debug stacks should not be error.

[Nerivec]

I suggest we add the (error as Error).message to the end of the above logging line (the already error one) and keep the error stack debug.
That should keep it in line with the rest of the code.

[Koenkk]

thanks!