Remove duplicated data from legacy events

When event-tracking was fully integrated into the platform, some data was replicated in the context in the middleware and then later extracted and moved the old location by event-tracking. The legacy code path was not updated to remove this transient shim data from the context resulting in duplication of the information. This patch ensures that the transient information is removed from the context before emitting the event.

Fixes: AN-2369
Add Eng (GB) and Albanian lang codes
Update translations (autogenerated message)
Merge pull request #4672 from edx/sarina/080414-translation-update

Sarina/080414 translation update
Merge pull request #4566 from mulby/remove-duplicate-context-fields

Remove duplicated data from legacy events
BLD 1020: Easy access to Group Configurations page from Content Experiment component.