Release video window when not used anymore

app/src/main/java/org/linhome/ui/call/CallInProgressActivity.kt

@@ -119,6 +119,7 @@ class CallInProgressActivity : CallGenericActivity() {
         if (coreContext.core.callsNb > 0) {
             coreContext.createCallOverlay()
         }
+	coreContext.core.nativeVideoWindowId = null
         super.onPause()
     }
 

app/src/main/java/org/linhome/ui/call/CallIncomingActivity.kt

@@ -78,4 +78,9 @@ class CallIncomingActivity : CallGenericActivity() {
             if (callViewModel.videoFullScreen.value!!) binding.root.videofullscreen else binding.root.videocollapsed
     }
 
+    override fun onPause() {
+        coreContext.core.nativeVideoWindowId = null
+        super.onPause()
+    }
+
 }