Fixing bad button style

Removing unneeded styling on confirmation button; making the
appearance and hover/focus behavior of the button match that
of the confirmation dialog in studio.

TNL-3189

lms/static/sass/_developer.scss

@@ -322,3 +322,23 @@
   }
 }
 
+//efischer - TNL-3189
+//copied from cms/static/sass/elements/_system-feedback.scss#L106
+//along with some "hide the inherited value, we want none" action
+.prompt.warning button {
+  @extend %btn-no-style;
+  box-shadow: none;
+  text-shadow: none;
+
+  &:hover {
+    color: $orange-s2;
+    background: transparent;
+    box-shadow: none;
+  }
+
+  &:focus {
+    box-shadow: none;
+    border: 0px;
+  }
+}
+