Reland "chrome_ti50: fail test if "externally driven!" message shows up"

This is a reland of commit 024ceca55992a58a1469f5a5e0c167aecf3fe2cf

Original change's description:
> chrome_ti50: fail test if "externally driven!" message shows up
>
> "externally driven!" means that the external WP signal doesn't match the
> WP state ti50 is trying to set. It shouldn't happen. Servod sets the
> ti50 WP state before driving the signal.
>
> Fail the test if "externally driven!" shows up in the logs, so we can
> see what tests trigger the issue.
>
> This CL may need to be reverted if it causes a lot of tests to fail.
>
> BUG=none
> TEST=none
>
> Change-Id: Id5c971ab998f423628d879e0bbe69139446ba5e5
> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/5916831
> Tested-by: Mary Ruthven <mruthven@chromium.org>
> Reviewed-by: Jett Rink <jettrink@google.com>
> Commit-Queue: Mary Ruthven <mruthven@chromium.org>

Bug: none
Change-Id: I311d50d4d69c9711da59cc0ef8807cd540db829d
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/6067031
Commit-Queue: Jett Rink <jettrink@google.com>
Reviewed-by: Jett Rink <jettrink@google.com>
Auto-Submit: Mary Ruthven <mruthven@chromium.org>
Tested-by: Mary Ruthven <mruthven@chromium.org>
diff --git a/server/cros/servo/chrome_ti50.py b/server/cros/servo/chrome_ti50.py
index 6602019..1d9ef62 100644
--- a/server/cros/servo/chrome_ti50.py
+++ b/server/cros/servo/chrome_ti50.py
@@ -125,7 +125,8 @@
     ERROR_DESC_LIST = [
             # b/254309086 AP RO verification messages about WP state.
             # This message means WP is externally driven. It shouldn't happen.
-            ['externally driven!', False],
+            # Fail if it shows up in the logs.
+            ['externally driven!', True],
             # This message shows up when the AP would have been rebooted due to
             # an external event such as WP being driven high (e.g. via
             # servo_micro), if WP we re-enabled, or if the AP RO verification