[mirotalksfu] - add triangle obj to whiteboard

public/views/Room.html

@@ -408,6 +408,7 @@ access to use this app.
                     <button id="whiteboardTextBtn" class="fas fa-spell-check"></button>
                     <button id="whiteboardLineBtn" class="fas fa-slash"></button>
                     <button id="whiteboardRectBtn" class="far fa-square"></button>
+                    <button id="whiteboardTriangleBtn" class="fas fa-triangle-exclamation"></button>
                     <button id="whiteboardCircleBtn" class="far fa-circle"></button>
                     <button id="whiteboardSaveBtn" class="fas fa-save"></button>
                     <button id="whiteboardEraserBtn" class="fas fa-eraser"></button>