android_ip_webcam: Fix motion_detect switch description (#13827)

There is no motion_detection but there is motion_detect as per:

grep motion_detect lib/python3.8/site-packages/homeassistant/components/android_ip_webcam/__init
__.py
    "motion_detect": "Motion Detection",
    "motion_detect",

This replaces the switch name with a correct one and adds it to
the config example. The switch is confirmed to work.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

source/_integrations/android_ip_webcam.markdown

@@ -103,7 +103,7 @@ switches:
       description: Control the focus.
     gps_active:
       description: Control the GPS.
-    motion_detection:
+    motion_detect:
       description: Control the motion detector.
     night_vision:
       description: Control the night vision.
@@ -151,6 +151,7 @@ android_ip_webcam:
       - ffc
       - focus
       - gps_active
+      - motion_detect
       - night_vision
       - overlay
       - torch