UpgradeImageGallery considers file extension when upgrading to 6.1

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 6.1.0 CE GA1, 6.1.10 EE GA1, 6.2.0 CE M2
• Fix Version/s: 6.1.10 EE GA1, 6.1.20 EE GA2, --Sprint 11/12, 6.2.0 CE M2
• Component/s: None
• Labels: None
• Branch Version/s:
  6.1.x
• Backported to Branch:
  Committed
• Fix Priority: 3
• Added to Fix Pack:
  Added
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/5269

Since all files that are in the IG can be considered safe and wanted, there is no point in checking dl.file.extensions during the upgrade. This especially is an issue in setups where no new file uploads of a specific type are allowed, while legacy files types have to be kept in the system.