Fix: moving lens views behind extension views (#1565)

* Moving lens-views behind extension views

Signed-off-by: Alex Andreev <alex.andreev.email@gmail.com>

* Setting z-index for all child elements of <main/>

Signed-off-by: Alex Andreev <alex.andreev.email@gmail.com>

src/renderer/components/cluster-manager/cluster-manager.scss

@@ -9,6 +9,10 @@
     grid-area: main;
     position: relative;
     display: flex;
+
+    > * {
+      z-index: 1;
+    }
   }
 
   .ClustersMenu {