ESS-DIVE metadata synchronization fails with empty measurementTechnique

[gilbertozp]

Metadata synchronization between NGEE-Tropics Archive and ESS-DIVE fails with error:
{"detail": "One or more fields raised validation errors.", "errors": ["measurementTechnique [''] is not valid under any of the given schemas"]}

This is happening with dataset 84 (NGT0084-v1.0: Transfer Test 8/3) within the ngt-dev environment. See also ESS-DIVE transfer log 82 (/admin/archive_api/essdivetransfer/82/)

[gilbertozp]

New tests attempted:

• created new minimal dataset, sync works (submit, approve, etc., before sync);
• then added "method description" to new dataset, sync still works;
• finally removed "method description" from new dataset, making field empty, sync still works;

So cannot reproduce issue affecting dataset 84 this way.