Remove unused code from Linkedin module

fixes: CNVS-12494

test plan:
* regression test for linkedin

Change-Id: Ibf6c78d767301184bc487813384f7c33ad78997a
Reviewed-on: https://gerrit.instructure.com/33428
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Simon Williams <simon@instructure.com>
QA-Review: Trevor deHaan <tdehaan@instructure.com>
Product-Review: Jason Madsen <jmadsen@instructure.com>