MAGETWO-92321: [Tech Debt] Cleanup master format for text

- Removed uneeded class

Author: nathanjosiah

app/code/Magento/PageBuilder/view/adminhtml/web/template/content-type/text/default/preview.html

@@ -7,6 +7,6 @@
 
 <div class="pagebuilder-content-type pagebuilder-text" event="{ mouseover: onMouseOver, mouseout: onMouseOut }, mouseoverBubble: false">
     <div class="pagebuilder-text" if="data.main.html()" attr="data.main.attributes" ko-style="data.main.style" css="data.main.css" html="data.main.html"></div>
-    <div class="placeholder-text" ifnot="data.main.html()" attr="data.main.attributes" ko-style="data.main.style" css="data.main.css" translate="'Text'"></div>
+    <div ifnot="data.main.html()" attr="data.main.attributes" ko-style="data.main.style" css="data.main.css" translate="'Text'"></div>
     <render args="getOptions().template" />
 </div>