Contao Captcha throws a JavaScript Error in the backend

[zoglo]

Affected version(s)

4.13, 5.3, 5.4

Description

Simply add the original security question captcha field within tl_form_field (in the backend) and wait a few seconds for the error to appear in console

/cc @ausi

[ausi]

Can confirm. The error reads Uncaught (in promise) TypeError: e.form is null in my test.

We should probably not output the captcha javascript in the backend.