Add attribute to show who last un/set alarm (SPC) (#9906)

* Add attribute to show who last un/set alarm.

This allows showing the name of the SPC user who last
issued an arm/disarm command and also allows for
automations to depend on this value.

* Optimize

* Update spc.py

* Update spc.py

* fix

* Fix test.

* Fix for removed is_state_attr.

tests/components/binary_sensor/test_spc.py

@@ -30,7 +30,7 @@ def test_setup_platform(hass):
         'area_name': 'House',
         'input': '0',
         'status': '0',
-        }, {
+    }, {
         'id': '3',
         'type': '0',
         'zone_name': 'Hallway PIR',
@@ -38,7 +38,7 @@ def test_setup_platform(hass):
         'area_name': 'House',
         'input': '0',
         'status': '0',
-        }, {
+    }, {
         'id': '5',
         'type': '1',
         'zone_name': 'Front door',
@@ -46,7 +46,7 @@ def test_setup_platform(hass):
         'area_name': 'House',
         'input': '1',
         'status': '0',
-        }]}
+    }]}
 
     def add_entities(entities):
         nonlocal added_entities