Remove Test_MSG_PrintMsg in favor of UT_DisplayPkt

[skliper]

Is your feature request related to a problem? Please describe.
Test_MSG_PrintMsg was added with MSG module, but duplicates what UT_DisplayPkt already did. No need for both.

Describe the solution you'd like
Replace Test_MSG_PrintMsg with UT_DisplayPkt and remove.

Describe alternatives you've considered
None.

Additional context
None.

Requester Info
Jacob Hageman - NASA/GSFC

[skliper]

Also should remove Test_MSG_Sum, this was just a lazy way to check a message that is no longer used anyways (didn't end up working well when default values that may be overwritten based on implementation are involved). Basically test_msg_utils.[ch] can go away.