Add missing already_scanning string

Change-Id: I87f97a60ab88b5b2be8cd66394ae532b5ad648d6
(cherry picked from commit 580ca93ea1296283314f2653f489c314f2f9e86f)
diff --git a/connectivity/bluetooth/BluetoothAdvertisements/Application/src/main/res/values/strings.xml b/connectivity/bluetooth/BluetoothAdvertisements/Application/src/main/res/values/strings.xml
index 0ea9c83..197178d 100644
--- a/connectivity/bluetooth/BluetoothAdvertisements/Application/src/main/res/values/strings.xml
+++ b/connectivity/bluetooth/BluetoothAdvertisements/Application/src/main/res/values/strings.xml
@@ -25,5 +25,6 @@
     <string name="empty_list">No devices found - refresh to try again.</string>
     <string name="seconds">seconds.</string>
     <string name="scan_start_toast">Scanning for</string>
+    <string name="already_scanning">Scanning already started.</string>
 
 </resources>
\ No newline at end of file