remove extra closing div tag
remove extra closing div tag

fixes CNVS-33112

test plan:
- go to a course hompage, set as the syllabus, for a public course where
you are not enrolled (so that you see the "Join Course" button
- it should have 1 right sidebar, not 2

Change-Id: I63c53cbca04f1b5c9e931a7056f5d74b7af532c8
Reviewed-on: https://gerrit.instructure.com/94414
Reviewed-by: Rob Orton <7e09c9d3e96378bf549fc283fd6e1e5b7014cc33@instructure.com>
Tested-by: Jenkins
QA-Review: Benjamin Christian Nelson <4a283f6b032925e40a485c88ede5597d7d65a090@instructure.com>
Product-Review: Simon Williams <088e16a1019277b15d58faf0541e11910eb756f6@instructure.com>

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