chore(column groups demo): hiding empty columns

Author: kdinev

src/app/grid-column-groups/grid-column-groups.sample.html

@@ -14,7 +14,7 @@
                 <igx-grid-toolbar-exporter></igx-grid-toolbar-exporter>
             </igx-grid-toolbar-actions>
         </igx-grid-toolbar>
-        <igx-column [resizable]="true"  field="Missing"></igx-column>
+        <!-- <igx-column [resizable]="true"  field="Missing"></igx-column> -->
         <igx-column-group header="General Information" title="General Company Information" [collapsible]="true" [expanded]="true" [hidden]="true">
             <igx-column [filterable]="false" [hidden]="true" [sortable]="true" [resizable]="true" field="CompanyName" title="Company Name" width="200px" [visibleWhenCollapsed]="false"></igx-column>
             <igx-column  field="Missing"></igx-column>
@@ -34,6 +34,7 @@
             <igx-column [filterable]="true" [sortable]="true" [resizable]="true" field="Address" [visibleWhenCollapsed]="false"></igx-column>
             <igx-column [filterable]="true" [editable]="true" [sortable]="true" [visibleWhenCollapsed]="true" field="FullAddress"></igx-column>
         </igx-column-group>
+        <!-- <igx-column  field="Missing"></igx-column>
         <igx-column  field="Missing"></igx-column>
         <igx-column  field="Missing"></igx-column>
         <igx-column  field="Missing"></igx-column>
@@ -44,8 +45,7 @@
         <igx-column  field="Missing"></igx-column>
         <igx-column  field="Missing"></igx-column>
         <igx-column  field="Missing"></igx-column>
-        <igx-column  field="Missing"></igx-column>
-        <igx-column  field="Missing"></igx-column>
+        <igx-column  field="Missing"></igx-column> -->
         <igx-column-group header="Address Information">
             <igx-column-group header="Location">
                 <igx-column [filterable]="true" [sortable]="true" [resizable]="true" field="Country"></igx-column>