adds check on template vars

Author: anshooarora

src/main/resources/com/aventstack/extentreports/templates/commons/commons-variables.ftl

@@ -1,8 +1,8 @@
 <#assign 
   config=this.config()
-  theme=config.theme?lower_case
+  theme=""
   timeStampFormat=config.timeStampFormat
-  offline=config.offlineMode
+  offline=false
   reportType=""
   parentHeading="Tests"
   childHeading="Steps"
@@ -12,6 +12,8 @@
   chartHeight="90"
   chartBoxHeight="94"
   displayEvents=true>
+<#if config.theme??><#assign theme=config.theme?lower_case></#if>
+<#if config.offlineMode??><#assign offline=config.offlineMode></#if>
 <#if report.stats.analysisStrategy=="SUITE">
   <#assign
     parentHeading="Suite"