Bug 7567: (follow-up) make tests of get_opac_new more readable

Bug 7567: (follow-up) make tests of get_opac_new more readable

This patch updates two of the tests cases to directly compare
the results returned by get_opac_new with the expected value
by using is_deeply().  Consequently, it removes the use of magic
numbers (which do not stop being magic numbers if they're wrapped
in constants named F1, F2, etc.).

To test:

[1] Verify that prove -v t/db_dependent/NewsChannels.t passes.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>