Add-ons Gift Upgrades 2.4.3

• Fix anonymous gifts not being marked as anonymous as expected.
• Fix "Cannot call method canGiftTo on a non-object (NULL)".
• Fix incorrect visibity on the _postDelete() method in the GiftUpgrade entity.
• Fix a potential issue where gifted upgrades were not marked as such.
• Add additional indexes to xf_user_upgrade_expired/xf_user_upgrade_active tables.

• Only inject User Essentials templates if that add-on is active.

• Add icon back to the "Gift" button.
• Allow sending free gifts from the account upgrades page.
• Fix a no permissions error that could occur when gifting from the account upgrades page.