Simplify message action logic to avoid unreachable branch

[skliper]

Checklist (Please check before submitting)

• I reviewed the Contributing Guide.
• I reviewed the README file to see if the feature is in the major future work.
• I performed a cursory search to see if the feature request is relevant, not redundant, nor in conflict with other tickets.

Is your feature request related to a problem? Please describe.
Branch can't be covered since there's no way to get to this decision with a ActionType <= HS_AMT_ACT_LAST_NONMSG:

HS/fsw/src/hs_monitors.c

Lines 182 to 184 in 2fc0dd9

	if ((HS_AppData.MsgActsState == HS_STATE_ENABLED) &&
	(ActionType > HS_AMT_ACT_LAST_NONMSG) &&
	(ActionType <= (HS_AMT_ACT_LAST_NONMSG + HS_MAX_MSG_ACT_TYPES)))

This is due to ActionType already being checked here:

HS/fsw/src/hs_monitors.c

Line 64 in 2fc0dd9

if ((ActionType != HS_AMT_ACT_NOACT) && (HS_AppData.AppMonCheckInCountdown[TableIndex] != 0))

All other cases of current implementation are handled. Only way to exercise this decision as false would be to introduce a bug.

Describe the solution you'd like
Slight refactor to simplify and allow full coverage - remove the NOACT case since it can never happen:

HS/fsw/src/hs_monitors.c

Line 177 in 2fc0dd9

case HS_AMT_ACT_NOACT:

Also swap the logic to calculate MsgActsIndex first and just check the result for in-range.

Describe alternatives you've considered
Could do enabled check first, but it's already 9 levels deep. Better to save that for #5 to really clean up duplicated logic.

Additional context
None

Requester Info
Jacob Hageman - NASA/GSFC