To make this Dashboard 2.0 friendly, you'd adjust:
<div class="wrapper">
<div class="fluid" style="height:{{msg.payload}}%"></div>
<div class="frame"></div>
<div class="txt">{{msg.payload}}%</div>
</div>
to be:
<div class="wrapper">
<div class="fluid" :style="'height:' + msg.payload + '%'"></div>
<div class="frame"></div>
<div class="txt">{{msg.payload}}%</div>
</div>
or, if you want to use Template Literals syntax:
<div class="wrapper">
<div class="fluid" :style="`height:${msg.payload}%`"></div>
<div class="frame"></div>
<div class="txt">{{msg.payload}}%</div>
</div>
Detail on why in our docs: Template ui-template | Node-RED Dashboard 2.0