Add BT_HCI_UNKNOWN_MESSAGE_TYPE log event

If the received HCI type is unknown, then log an event and abort.
The most likely reason for that to happen is if the UART stream
is corrupted. We cannot recover from that, and there is not much
else we can do.

Also, fixed a bug in an HCI-related unit test that was exposed
by the above change.

Bug: 31432127
Change-Id: Ia888c485f177af4962268bf8f593b27fd7a4b080
diff --git a/EventLogTags.logtags b/EventLogTags.logtags
index 32493d8..dc1d239 100644
--- a/EventLogTags.logtags
+++ b/EventLogTags.logtags
@@ -35,3 +35,4 @@
 
 1010000 bt_hci_timeout (opcode|1)
 1010001 bt_config_source (opcode|1)
+1010002 bt_hci_unknown_type (hci_type|1)