Handle LOK_CALLBACK_TOOLTIP in wsd

Send "tooltip: <payload>" to client for this callback type.
Client-side handling should be implemented separately.

Signed-off-by: Mike Kaganski <mike.kaganski@collabora.com>
Change-Id: I2d1a07dd36fa20a4b5ff785da788356e0f41d62f

kit/ChildSession.cpp

@@ -3223,6 +3223,11 @@ void ChildSession::loKitCallback(const int type, const std::string& payload)
         sendTextFrame("corelog: " + payload);
         break;
     }
+    case LOK_CALLBACK_TOOLTIP:
+    {
+        sendTextFrame("tooltip: " + payload);
+        break;
+    }
     default:
         LOG_ERR("Unknown callback event (" << lokCallbackTypeToString(type) << "): " << payload);
     }