Dashboard: Refactor container css to use flex for height instead of calc (#24009)

* Dashboard: Ability to hide dashboard toolbar

* Updated snapshot

public/sass/components/_dashboard_grid.scss

@@ -16,13 +16,7 @@
 
 .panel-in-fullscreen {
   .react-grid-layout {
-    height: 100% !important;
-  }
-
-  .dashboard-container--has-submenu {
-    .react-grid-layout {
-      height: calc(100% - 50px) !important;
-    }
+    height: 90% !important;
   }
 
   .react-grid-item {

public/sass/components/_panel_editor.scss

@@ -5,8 +5,6 @@
   &--view {
     flex: 1 1 0;
     height: 90%;
-    margin: 0 $dashboard-padding;
-    padding-top: $dashboard-padding;
   }
 }
 
@@ -28,14 +26,6 @@
     display: none;
   }
 
-  .dashboard-container {
-    padding: 0;
-  }
-
-  .submenu-controls {
-    padding: 0 $dashboard-padding $space-sm $dashboard-padding;
-  }
-
   .search-container {
     left: 0 !important;
   }