Remove ignored message from wiredtiger_open in test_encrypt08

WT-7799 removed the print on stdout upon failure of wiredtiger_open; this broke the new test_encrypt08 from WT-7832, which had needed to account for that print. This is partly my fault: I mentioned that some tests expected to see the print, but then neglected to follow up that I'd needed to do the same thing with my then-pending new test. It's also likely that the tests are being skipped by default most of the time.

Anyway, it broke and the fix is straightforward.