Fix #1360, Limit HK Commands to 1 in pipe + replace hand-written function names with `__func__`

[thnkslprpt]

Checklist

• [x] I reviewed the Contributing Guide.
• [x] I signed and emailed the appropriate Contributor License Agreement to [email protected] and copied [email protected].

Describe the contribution

• Fixes #1360
  • Limits Send HK MIDs in the ES command pipe to 1 at a time using CFE_SB_SubscribeEx()
  • Also piggy-backing on this PR are a few typo fixes, updates to out-of-date identifiers, and replacing hand-written function names with __func__ (to reduce chances of these coming out of sync in the future)

Testing performed GitHub CI actions all passing successfully (incl. Build + Run, Unit/Functional Tests etc.).

Expected behavior changes Send HK MIDs in ES command pipe will be explicitly limited to 1 at a time instead of whatever the default is set to (currently 4).

Contributor Info Avi Weiss   @thnkslprpt

[skliper]

Changing to one was a code review suggestion. If there's more than one something is probably broken or at least extremely delayed and worth notifying the user (via the event from SB on msg limited). I can't imagine a use case for having more than one in the pipe, but maybe I'm not imaginative enough?