Fix #2488, separate bad argument test

[jphickey]

Checklist (Please check before submitting)

• I reviewed the Contributing Guide.
• I signed and emailed the appropriate Contributor License Agreement to GSFC-SoftwareRelease@mail.nasa.gov and copied cfs-program@lists.nasa.gov.

Describe the contribution
Pass in CFE_SB_INVALID_MSG_ID separately from a NULL pointer. This also required updates to the way the MSG module checks the MsgID, as it was not using the IsValidMsgID check.

Fixes #2488

Testing performed
Build and run all tests

Expected behavior changes
CFE_MSG_Init() will now return the BAD_ARGUMENT code if passed CFE_SB_INVALID_MSG_ID. Oddly, this was not the case previously, it would still return CFE_SUCCESS. This is because the MSG implementation wasn't using the same check function (CFE_SB_IsValidMsgID). This PR corrects that.

System(s) tested on
Debian

Additional context
This is correct behavior now, but its one of those things where I can't be totally sure if some app was relying on the incorrect behavior.

Contributor Info - All information REQUIRED for consideration of pull request
Joseph Hickey, Vantage Systems, Inc.

[jphickey]

@skliper --- do you know why the original "SetMsgId()" only checked against HIGHEST_VALID_MSGID instead of using the check implemented in SB? Was there a justification for having a different/lesser validation of MsgId in this particular code?

I'm curious because I don't see any real reason it should be more permissive, yet there seemed to be coverage tests checking for the fact that a msgID value of "0" can be successfully set.

[skliper]

I think that's just left over from when CFE_SB_INVALID_MSG_ID was not zero. I think at some point in history it was in a config file. With it now in the core_api the current tests to check for 0 being valid don't make sense to me.