[entropy_src/rtl] Remove redundant AlertState transition
[entropy_src/rtl] Remove redundant AlertState transition

This commit cleans up an inconsistency in the `main_sm` which has
been identified in FSM coverage maps.

Background:

In commit 84a680b3cf (PR #14391) the `entropy_src_main_sm` was
modified to check and trigger health test alerts _before_ starting the
SHA3 condititioner.  This is is important for verification which expects
failing entropy to remain in the conditioner until a successful health
check.  (Such is the behavior of the Startup Phase, though the
Continuous phase did not follow this convention at first).

However in PR #14391 the _original_ transition to the AlertState was
left in place.  This transition is still an error, because in the
Startup and Continuous phases, the alert checks are to be done when all
the health test results have been completed at the end of the health
test window.

This second post-SHA alert transition is theoretically still reachable,
and so it would not be removed by UNR coverage exclusions. It would
however take a very unusual set of coincidences to reach it. (For
example, a new health test failure, likely a REPCNT failure, would have
to occur immediately after the end of the previous successfull window,
while the SHA conditioner is still processing.) So it is unlikely to
be seen in verification, and it has never to my knowledge been seen in
FSM coverage.

It is still an incorrect transition which should have been removed
in PR #14391, particularly since the UNR analysis says that it could
still be triggered under some events.

Signed-off-by: Martin Lueker-Boden <7e82c17fafb3b7b91b3c3396a2f21a060e5a6c3d@wdc.com>

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