enable keyguard when users presses home button

= security check if call was entered via notification in locked mode

Signed-off-by: Marcel Hibbe <dev@mhibbe.de>

app/src/main/java/com/nextcloud/talk/activities/MagicCallActivity.kt

@@ -96,6 +96,7 @@ class MagicCallActivity : BaseActivity() {
 
     @RequiresApi(Build.VERSION_CODES.O)
     override fun onUserLeaveHint() {
+        enableKeyguard()
         enterPictureInPictureMode(getPipParams())
     }