API tests - label versions in dataprovider versionThreeAndFour

[colemanw]

Overview

In unit tests, make it more clear which api version is being tested.

Before

Numeric keys gave ambiguous messages like "Test xyz failed with dataset 0"

After

String keys should give more specific messages like "Test xyz failed with dataset 'APIv3'"

[civibot]

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[eileenmcnaughton]

(has-test = is test improvement)