source-braintree-native: fix nullable key on full refresh resources #959

Job	Run time
py_connector (source-airtable, capture, v1, 1.0)	2m 2s
py_connector (source-asana, capture, v1, 1.0)	2m 31s
py_connector (source-facebook-marketing, capture, v4, 1.0)	2m 18s
py_connector (source-gladly, capture, v1, 1.0)	1m 42s
py_connector (source-google-ads, capture, v2, 1.0)	2m 18s
py_connector (source-google-sheets-native, capture, v1, 0.0)	2m 7s
py_connector (source-hubspot-native, capture, v1, 1.0)	2m 9s
py_connector (source-hubspot, capture, v5, 1.0)	1m 12s
py_connector (source-notion, capture, v2, 1.0)	2m 24s
py_connector (source-oracle-flashback, capture, v1, 1.0)	52s
py_connector (source-linkedin-pages, capture, v1, 1.0)	2m 3s
py_connector (source-linkedin-ads-v2, capture, v1, 1.0)	1m 53s
py_connector (source-klaviyo, capture, v1, 1.0)	2m 6s
py_connector (source-recharge, capture, v1, 1.0)	1m 51s
py_connector (source-stripe-native, capture, v1, 1.0)	4m 8s
py_connector (source-zendesk-support, capture, v2, 1.0)	1m 44s
py_connector (source-iterable, capture, v2, 1.0)	2m 3s
py_connector (source-pendo, capture, v2, 1.0)	1m 44s
py_connector (source-twilio, capture, v2, 1.0)	1m 55s
py_connector (source-jira-native, capture, v2, 1.0)	1m 30s
py_connector (source-mixpanel-native, capture, v2, 1.0)	2m 2s
py_connector (source-brevo, capture, v1, 1.0)	2m 4s
py_connector (source-impact-native, capture, v2, 1.0)	1m 40s
py_connector (source-front, capture, v3, 1.0)	1m 6s
py_connector (source-genesys, capture, v1, 1.0)	1m 41s
py_connector (source-braintree-native, capture, v1, 1.0)	2m 27s
	51m 32s

Provide feedback