Setting overflow:hidden on lens-view elem (#664)

This prevents scrollbar flickering caused by Animation component
with 'slide-left' appearing.

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

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

@@ -14,6 +14,7 @@
   #lens-views {
     grid-area: main;
     display: flex;
+    overflow: hidden;
 
     &.active {
       z-index: 1;