Be more explicit for expected tibble outputs in unit tests

[lianos]

After dplyr 1.0 dropped, it became clear where the expect_equal() calls were implicitly ignore attribute checking: we create tibbles of expected output to test against, but the class attributes of the data returned from the facile api isn't just a plain tibble.

For now, these unit tests set expect_equal(returned, expected, **check.attributes = FALSE**) in order to ignore class matching. This is good enough for now since we are most interested in ensuring that the data we get back is sound.

It would be good to more explicitly test the class attributes of the data returned to help formalize what types of classes are returned from which API calls.

These are the unit test locations where check.attributes = FALSE needed to be added.

• test-assay-data.R#Line41
• test-entity-attribute-value.R#Line78
• test-feature-info.R#Line13
• test-feature-info.R#Line16
• test-sample-covariates.R#Line23
• test-samples.R#Line11