Superfluous assignments, side-effects. type updates etc.

Checklist

• I reviewed the Contributing Guide.
• I performed a cursory search to see if the bug report is relevant, not redundant, nor in conflict with other tickets.

Describe the bug
Some issues that can be easily cleaned up to improve readability and ease maintenance by simplifying the code.

• superfluous initializations (when the variable is immediately or always assigned a value before being used)
• side-effects in conditionals that can be easily removed and end up more readable
• a couple of types can be updated (size_t, CFE_MSG_FcnCode_t)

Code snips
Can be size_t:
https://github.com/nasa/CS/blob/bd4dd1ce688e9af683e63132b37306b21f320ab2/fsw/inc/cs_tbldefs.h#L370

Can be CFE_MSG_FcnCode_t:
https://github.com/nasa/CS/blob/bd4dd1ce688e9af683e63132b37306b21f320ab2/fsw/src/cs_app.c#L268

Several functions with multiple CS calls that could be made clearer and more compliant with an additional Status/Result variable. e.g.:
https://github.com/nasa/CS/blob/bd4dd1ce688e9af683e63132b37306b21f320ab2/fsw/src/cs_app_cmds.c#L215-L241

Expected behavior
Clear up where it makes sense.

Reporter Info
Avi Weiss @thnkslprpt

Start with fsw/inc/cs_tbldefs.h, fsw/src/cs_app.c, and fsw/src/cs_app_cmds.c at the linked locations. Review the surrounding code for unnecessary initializations, conditional side effects, type updates, and clearer status handling. Done means applying justified readability and maintenance cleanups while preserving behavior.