Fix ExtentHtmlReporter view issue on v3-html-bdd.ftl#L41

This issue is a follow-up from #120.  ExtentHtmlReporter does not log base64 images and defaults to file-path to link images to the report.  Suggested fix is to conditionally allow base64 here:

[View](https://github.com/extent-framework/extentreports-java/blob/master/src/main/resources/com/aventstack/extentreports/view/v3html/test-view/v3-html-bdd.ftl#L41)