Display style data handlers exports data too

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 6.2.10 EE GA1, 6.2.X EE, 7.0.0 M3
• Fix Version/s: 6.2.2 CE GA3 , 6.2.X EE, 7.0.0 M3
• Component/s: Staging, Staging > Export/Import
• Labels:
  • QA-TP
  • backend_test
  • liferay-fixpack-wcm-core-16-6210
• Branch Version/s:
  6.2.x
• Backported to Branch:
  Committed
• Story Points: 8
• Fix Priority: 4
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/19279

Reproduction steps:
1. Create a site
2. Add 2 or more web content articles to the site
3. Create a page in the site and place a web content display on it
4. Set up the web content display portlet and configure it to show one of the web contents
5. Export the web content display - only the portlet

Expected behavior: the web content display is exported, and the LAR contains only the referenced web content
Actual behavior: All the web contents are being exported

=== Technical background
The LAR file is actually a zip file and it can be checked if there are more than one web content has been exported. Check a similar path: /group/<groupId>/com.liferay.portlet.journal.JournalArticle/<id>.xml
Each xml file is a version of a web content so even if one content is exported depending on how many versions does it have this folder may contain more than one xml files