CFE_SB_NO_MESSAGE return from DS_AppMain causes unintended app exit

[chillfig]

Checklist (Please check before submitting)

• I reviewed the Contributing Guide.
• I reviewed the README file to see if the feature is in the major future work.
• I performed a cursory search to see if the feature request is relevant, not redundant, nor in conflict with other tickets.

Is your feature request related to a problem? Please describe.
due to a bad CRC discarding an incoming message, or when configured to poll with CFE_SB_POLL, cFE_SB_ReceiveBuffer returns CFE_SB_NO_MESSAGE which DS treats as fatal and exits.

Describe the solution you'd like
The app should continue

Describe alternatives you've considered
N/A

Additional context
Inherited from lunar gateway

Requester Info
Justin Figueroa, Vantage Systems Inc