Update UI link (#136)

The launch.adobe.com URL was discontinued some time ago, this commit updates the link to the correct destination.

Author: Carnix

api/index.md

@@ -5,8 +5,8 @@ layout: documentation
 
 # API First
 
-Launch, by Adobe is an entirely API-first application.  All system functionality is accessible through the API.  The UI at [launch.adobe.com](https://launch.adobe.com) is simply a friendly way to interact with them.
+Launch, by Adobe is an entirely API-first application.  All system functionality is accessible through the API.  The UI at [https://experience.adobe.com/#/data-collection](https://experience.adobe.com/#/data-collection) is simply a friendly way to interact with them.
 
 This API - known as the Reactor API - uses the JSON API specification.  We expect inputs to be compliant with this specification and all outputs are also compliant.  You can read more at [jsonapi.org](http://jsonapi.org/).
 
-The full API specification is available under Reference > 1.0 in the navigation.
+The full API specification is available under Reference > 1.0 in the navigation.