Error appearing when using the `create-account-template` command

[Toby-Masters-SF]

Describe the bug
Following error message appears when running create-account-template for an account template without the mapping_list_ranges field in the associated config.json file.

To Reproduce
Steps to reproduce the behavior:

1. Go to any account template without a mapping_list_ranges field / remove it from the config
2. Run create-account-template command

Expected behavior
The account template should be created or if the mapping_list_ranges is required a more useful error message should appear

Screenshots or Pull request

Desktop & CLI (please complete the following information):

• OS: Mac
• CLI version (run silverfin --version): 1.35.0

Additional context
N/A