When the TCI's configuration file has non-existing columns mapped, TCI should ignore those definitions

Description
When the TCI's configuration file comes from a previous Importation Process, it may have extra columns mapped. Right now, TCI is not ignoring those definitions, which leads to a console error.

How to reproduce

1. Have a CSV file with X columns defined;
2. Use a configuration file with X+1 columns mapped;
3. Go to the TCI, select the CSV and the configuration files;
4. Navigate through the importer until the "Map fields" window and press "Begin Import".

Actual result/Attachments
Nothing happens on the User's UI.
Console Error:

Console Log file: xpand-support-sandbox.atlassian.net-1614180612817.log

Expected result
TCI ignores the extra columns.