ES - RegisteredTasks Counter Does Not Decrement When Child Tasks are Exited

[skliper]

Stakeholder reported that the ES "RegisteredTasks" counter was not decrementing when a child task exited. The CS code was examined to ensure the needed ES API calls were being made. It was confirmed the CS child tasks make the ES API call to CFE_ES_ExitChildTask. The CFE_ES_ExitChildTask API function does decrement the RegisteredTasks counter on line 1337 however, this step is performed only if conditional checks are passed.

Really CS shouldn't dynamically be creating/exiting child tasks per a separate issue, but noted here still since it was an observed issue (although no steps provided to recreate).

Imported from GSFCCFS-951