fix non-working accessibility hidden text toggle
added aria landmark header to side nav
Merge branch 'master' of https://github.com/Stanford-Online/class2go into giulio-tpg-report-2290
removed unecessary function reference
Merge branch 'master' of https://github.com/Stanford-Online/class2go into giulio-tpg-report-2290
Merge pull request #2507 from Stanford-Online/giulio-tpg-report-2290

Final Accessiblity fixes for voiceover users