Dropping a dataset with an non-existent dataverse returns error 24034 (cannot find dataverse) in 6.6, but a "cannot find dataset" error in 6.5

We (Java SDK folk) are now running our CI tests against 6.6, which has found this minor regression.

The test is:

@Test

void dropDatasetFailsIfAbsent() {

    assertThrows(DatasetNotFoundException.class, () -> analytics.dropDataset("foo",

      dropDatasetAnalyticsOptions()

          .dataverseName("absentDataverse")));

}

In 6.6 this now fails as it raises a DataverseNotFoundException rather than DatasetNotFoundException, as cbas now returns a 24034 code.  In this test and the one below too, neither "foo" nor "absentDataverse" exist.

This causes problems for our `ignoreIfNotExist` option, which allows dropping datasets and silently ignoring if they don't exist.  Because that logic is expecting a DataverseNotFoundException. 

E.g. this other test fails with a DataverseNotFoundException, when you would expect it to succeed.  This test also passed in 6.5.

@Test

void dropDatasetCanIgnoreAbsent() {

  analytics.dropDataset("foo",

      dropDatasetAnalyticsOptions()

          .ignoreIfNotExists(true)

          .dataverseName("absentDataverse"));

}

 For both tests, if I don't specify a dataverseName then the tests pass as expected.