Fix menubar z-index

Author: Damian Martinez Gelabert

dist/styles/api-console-dark-theme.css

@@ -1236,6 +1236,7 @@ th {
   position: absolute;
   top: 0;
   right: 0;
+  z-index: 10px;
 }
 
 .raml-console-meta-button-container {

dist/styles/api-console-light-theme.css

@@ -1236,6 +1236,7 @@ th {
   position: absolute;
   top: 0;
   right: 0;
+  z-index: 10px;
 }
 
 .raml-console-meta-button-container {

src/scss/_header.scss

@@ -13,6 +13,7 @@
   position: absolute;
   top: 0;
   right: 0;
+  z-index: 10px;
 }
 
 .meta-button-container {