Use of JSON fields in template fails dashboard import

[thomas-gerber]

Describe the bug
The use of field derived from a JSON-containing column makes import fail on field-level table sync check.

To Reproduce
Steps to reproduce the behavior:

1. Start Faros
2. Import some tasks from Jira/GH/...
3. Trigger a database schema sync and field value scan
4. Check that tms_Task now has 2 versions of status category for tms_Task: the generated field statusCategory and the newly metabase-derived one status -> category
5. Create a dashboard with a non-SQL question using that status->category field as aggregation
6. Export the dashboard.
7. Try to re-import it.
8. Import fails on syncTable because the check can not find that field in the metadata.

Expected behavior
Dashboard import from a template using such field is successful.

Screenshots and logs
If applicable, add screenshots and logs to help explain your problem.
Example of bad template that had to be fixed here

Notice the difference between the 2 field types:

Encountered during #231 .