ns-render spiral does not work.

[Yoonho-Na]

Describe the bug
I want to make a video that renders spiral path but there is an assertion error

To Reproduce
Steps to reproduce the behavior:

1. execute the below line in terminal
   ns-render spiral --load-config your/path/to/config_file/config.yml --output-path renders/custom/output_filename.mp4

Expected behavior
render a video with spiral camera path

Screenshots

[kerrj]

#2637 should fix