Check added to resolve Ajax Container instantiation error in log

When using the Microsoft Internet Explorer or Microsoft Edge browsers, manually launching a Service Intent and clicking the F5 refresh button properly refreshed the screen, but the PegaRULES log file contained the error "(DynamicContainerDataModel) Error occurred while instantiating tab for the thread index." This issue / exception was observed only when pzCustomDCTabHeader was configured (pyEnableCustomTabHeaders) and when there was a AjaxContainer configured in the document. Because the CustomTabHeader recreation (DynamicContainerDataModel.updateCustomTabHeader) should be skipped for AjaxContainer, as CustomTabHeader is applicable only to the top level DC document and not to the AjaxContainer document, a check has been added to resolve this issue.