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
Allow external_auth registrations to bypass PW complexity check
Annotations Tools: Sharing Plugin Fixed with Proper URI
Annotation Tool: Fixing Table Share bug (2b)
Image Annotation Tool: Fixed Viewport Timeout Issue
Annotation Tools: Fixing Share Indentation, Grep Functions and Equality
Annotation Tools: Fixed Share button to allow selection of text box
Annotation Tools: Code clean-up, formatting, spacing
Disable css3 animations in bok-choy tests.
Annotation Tool: Bug Fix Filtered Personal Annotations on Page Load

- Made sure that all highlights were removed.

- Forgot closing parens

- added comments to fix
Annotation Tools: Spacing Issues fixed for catch.js
update bok choy db caches
Merge pull request #4166 from lduarte1991/lduarte-harvardx-pr5

Annotations Tools: Sharing Plugin Fixed with Proper URI
Removed info about ORA-51
Merge pull request #4637 from edx/sylvia/docs/relnotesupdate

Removed info about ORA-51
Disable video handout tests
Merge pull request #4351 from lduarte1991/lduarte-harvardx-pr8

Annotation Tool: Bug Fix Filtered Personal Annotations on Page Load
Merge pull request #4629 from edx/anton/disable-css-animations-in-bok-choy

Disable css3 animations in bok-choy tests.
Merge pull request #4643 from edx/zoldak/disable-video-handout-tests

Disable video handout tests
Annotator Tools: Fixing annotator break in login and dashboard