Use sized char array for CFE_SB_GetAppTskName parameter and limit print

[skliper]

Is your feature request related to a problem? Please describe.
CFE_SB_GetAppTskName takes a char pointer FullName without an associated size. Relies on user to size the buffer correctly for the sprintf:

cFE/modules/sb/fsw/src/cfe_sb_priv.c

Line 304 in c8b5e00

char *CFE_SB_GetAppTskName(CFE_ES_TaskId_t TaskId, char *FullName)

cFE/modules/sb/fsw/src/cfe_sb_priv.c

Line 335 in c8b5e00

sprintf(FullName, "%s.%s", AppName, TskName);

Describe the solution you'd like
Related to #1457, explicitly size as an array and use snprintf to print to limit appropriately. Note #994 suggests moving this to a generic utility (out of SB scope), maybe ES API.

Describe alternatives you've considered
None

Additional context
Code review

Requester Info
Jacob Hageman - NASA/GSFC