Postgres capture bindings are not defaulting properly

[travjenkins]

Bug1
New capture
select postgres
Enter endpoint config
Discover
Get results
See the next button show

Expected
The next button does not show

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Bug 1
Create / publish a postgres capture with at least 2 bindings
Edit same capture
Click on second binding in resource config editor
See the next button appear because mode was defaulted to an empty string ""

Expected
The next button does not display
The field is not defaulted to an empty string

Screenshots
The initial discover is not defaulting mode to an empty string on the backend

Desktop (please complete the following information):
N/A

Additional context
Might end up being an issue we just have to deal with