feat(system_diagnostic_monitor): add vehicle emergency button (autowarefoundation#846)

Signed-off-by: Makoto Kurihara <mkuri8m@gmail.com>

Author: mkuri

autoware_launch/config/system/system_diagnostic_monitor/vehicle.yaml

@@ -32,6 +32,7 @@ units:
     type: and
     list:
       - { type: link, link: /vehicle/006-vehicle_errors }
+      - { type: link, link: /vehicle/007-vehicle-emergency-button }
 
   - path: /vehicle/pull_over
     type: and
@@ -86,3 +87,9 @@ units:
     node: j6_interface
     name: vehicle_errors
     timeout: 1.0
+
+  - path: /vehicle/007-vehicle-emergency-button
+    type: diag
+    node: j6_interface
+    name: vehicle_emergency_button
+    timeout: 1.0