removes a couple of calls to Array.slice() where they are not needed.

[stopfstedt]

refs ilios/ilios#5660

i made another pass of the frontend package and checked on any calls on slice().

$ grep -lr '\.slice()' packages/frontend | egrep -v '(dist|node_modules)' | sort
packages/frontend/app/components/courses/root.js
packages/frontend/app/components/global-search-box.js
packages/frontend/app/components/instructor-groups/list.js
packages/frontend/app/components/new-directory-user.js
packages/frontend/app/components/program-year/objective-list.js
packages/frontend/app/components/reports/subject/new/course.js
packages/frontend/app/components/reports/subject/new/session.js
packages/frontend/app/components/reports/subject/session.js
packages/frontend/app/controllers/curriculum-inventory-report/index.js
packages/frontend/tests/integration/components/program-year/list-test.js

a couple of them can be removed, the rest is necessary.

will deal with the other packages at a later time, unless someone else beats me to it.

[michaelchadwick]

De-slice()d!