doc: peripheral_lbs - Add images for the button examples

Peripheral_lbs sample:

* A screenshot of how to enable notifications
(or at least explain the icon: downward arrow with bottom line)
* A screenshot of writing value (up arrow) + showing "Bool" selected

NCSDK-35994

Signed-off-by: divya pillai <[email protected]>

Author: divipillai

doc/nrf/images/nRF Connect_enable_notify.png

@@ -152,14 +152,20 @@ After programming the sample to your dongle or development kit, one of the LEDs
             #. Connect to the device from the application.
                The device is advertising as ``Nordic_LBS``.
                The services of the connected device are shown.
-            #. In **Nordic LED Button Service**, enable notifications for the **Button** characteristic.
+            #. In **Nordic LED Button Service**, enable notifications for the **Button** characteristic, using the downward arrow icon.
+
+               .. figure:: /images/nRF Connect_enable_notify.png
+
             #. Press **Button 1** on the device.
             #. Observe that notifications with the following values are displayed:
 
                * ``Button released`` when **Button 1** is released.
                * ``Button pressed`` when **Button 1** is pressed.
 
-            #. Write the following values to the LED characteristic in the **Nordic LED Button Service**.
+            #. Write the following values to the LED characteristic in the **Nordic LED Button Service**, using the up arrow icon.
+
+               .. figure:: /images/nRF Connect_write.png
+
                Depending on the hardware platform, this produces results described in the table.
 
                +------------------------+---------+----------------------------------------------+
@@ -188,14 +194,20 @@ After programming the sample to your dongle or development kit, one of the LEDs
             #. Connect to the device from the application.
                The device is advertising as ``Nordic_LBS``.
                The services of the connected device are shown.
-            #. In **Nordic LED Button Service**, enable notifications for the **Button** characteristic.
+            #. In **Nordic LED Button Service**, enable notifications for the **Button** characteristic, using the downward arrow icon.
+
+               .. figure:: /images/nRF Connect_enable_notify.png
+
             #. Press **Button 0** on the device.
             #. Observe that notifications with the following values are displayed:
 
                * ``Button released`` when **Button 0** is released.
                * ``Button pressed`` when **Button 0** is pressed.
 
-            #. Write the following values to the LED characteristic in the **Nordic LED Button Service**.
+            #. Write the following values to the LED characteristic in the **Nordic LED Button Service**, using the up arrow icon.
+
+               .. figure:: /images/nRF Connect_write.png
+
                Depending on the hardware platform, this produces results described in the table.
 
                +------------------------+---------+----------------------------------------------+