title: p-footer is not a known element error in p-dialog
body: <blockquote>
    <p>in html</p>
  </blockquote>
  
  <pre><code>&lt;p-dialog [resizable]="false" header="Softcopy Acceptance for Ledger and 
  Invoice" [(visible)]="!displaySoftCopyDialog"
  [responsive]="true" showEffect="fade" [modal]="true" [width]="600"&gt;
  
  &lt;p style="margin: 5px; height: 305px"&gt;&lt;span&gt;
  &lt;span style="color:red;"&gt;GO GREEN&lt;/span&gt;&lt;br&gt;
  Season’s Greetings! &lt;br&gt;
  copy, they may consciously opt for the Hardcopy option.&lt;br&gt;&lt;br&gt;
  We wish for your consent to join us in this drive by opting for monthly 
  bills through E-bill only.
  &lt;/span&gt;&lt;/p&gt;
  &lt;p-footer&gt;
  &lt;div class="ui-dialog-buttonpane ui-widget-content ui-helper-clearfix"&gt;
      &lt;button type="submit" class="btn btn_searchSmall_add" 
  (click)="remindSoftCopy()"&gt;Remind Later&lt;/button&gt;
      &lt;button type="submit" class="btn btn_searchSmall_add" 
  (click)="acceptSoftCopy()"&gt;Accept&lt;/button&gt;
  &lt;/div&gt;
   &lt;/p-footer&gt;
  &lt;/p-dialog&gt;
  </code></pre>
  
  <blockquote>
    <p>in ts file i seted these 2 from primeng</p>
  </blockquote>
  
  <pre><code>DialogModule,
  SharedModule
  </code></pre>
  
  <blockquote>
    <p>in module also i seted these 2 from primeng</p>
  </blockquote>
  
  <pre><code>DialogModule,
  SharedModule
  </code></pre>
  
  <blockquote>
    <p>why this happens</p>
  </blockquote>