Fix mobile/minimal layout layout (#5381)

fix #5386, fix #5023

(cherry picked from commit a545279)

Author: nilmerg

public/css/icinga/responsive.less

@@ -70,7 +70,11 @@
 #layout.minimal-layout {
   #sidebar {
     width: 100%;
-    overflow: auto;
+
+    &.expanded {
+      overflow: auto;
+      height: 100%;
+    }
   }
 
   #header-logo-container {