Remove remaining stray uses of sprintf()

[thnkslprpt]

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
A few stray uses of sprintf() remain in cFE (mostly in the test code, but not entirely).
The simple cases will be converted to snprintf() to enforce a maximum size for the buffer being written into.
A couple of cases have their own issues open already with further changes being considered, so I will probably leave those to be addressed there (#1465 and #1511)

Expected behavior
No use of sprintf() in the code base (including test code).

Code snips

cFE/modules/es/fsw/src/cfe_es_cds.c

Line 662 in be88a07

sprintf(FullCDSName, "%s.%s", AppName, CDSName);

cFE/modules/cfe_testcase/src/tbl_content_access_test.c

Line 121 in be88a07

sprintf(TblName, "%d", i);

Reporter Info
Avi Weiss @thnkslprpt

Previous discussion opening this issue:
I concur that snprintf has some caveats/dangers - particularly with respect to the return code and handling that properly - whereas sprintf() is a buffer overflow exploit in almost all use-cases, and should rightfully be banned.
Originally posted by @jphickey in #824 (comment)

There are still a few stray uses of sprintf() across cFS. Should these be removed?

[skliper]

Yeah, that would be a good update from my point of view. Most of it's in tests which might not be a high priority, but there's a handful of flight code use still.