contrib.vector maps are hard-coded to use cloud

[andy-esch]

We need to set the serverURL in CARTO VL's code here:

cartoframes/cartoframes/assets/vector.html

Lines 46 to 49 in dbe58ff

	carto.setDefaultAuth({
	user: credentials['user'],
	apiKey: credentials['api_key'] || 'default_public'
	});

This will allow vector maps to work with On Prem releases

[andy-esch]

closed in #505