enhance: remove border radius for property key bullet

To difference properties from block content.

src/main/frontend/components/property.css

@@ -177,8 +177,8 @@ input.simple-input:focus {
     }
 }
 
-.property-key .bullet-container .bullet, .ls-property-input .bullet-container .bullet {
-    background-color: darkgrey;
+.property-key .bullet-container, .property-key .bullet-container .bullet {
+    border-radius: 0px;
 }
 
 /* TODO:  */