Begin new A/B test for data landing page

[JonellaCulmer]

What we're after:
Begin new A/B test to compare default to new possible variation of the data landing page

Related issues:

• End data landing page experiment #5087

Completion criteria:

• New A/B test begins comparing default to new variation

Designs: new variation

[JonellaCulmer]

@rfultz Here's a link to the implementation ticket for adding the message for the missing map: #5210 (comment)