Add a second delay() to get the unit tests running on Rak4631

[jp-bennett]

Testing... If you don't see any output for the first 10 secs, please reset board (press reset button)

test/test_crypto/test_main.cpp:136: test_SHA256 [PASSED] test/test_crypto/test_main.cpp:137: test_ECB_AES256 [PASSED] test/test_crypto/test_main.cpp:138: test_DH25519 [PASSED] test/test_crypto/test_main.cpp:139: test_AES_CTR [PASSED] --------------------------------------------------------------------- rak4631:test_crypto [PASSED] Took 97.32 seconds ---------------------------------------------------------------------