Revert "Swapped out placeholder text from team admin page"

This reverts commit 21c7121f8d67c5a53aa36d59171f6bb402fc2384.
Swapped out placeholder text from team admin page

Removed "simple Teams description" in favor of "allow you to organize
groups of people that have a common focus. Use teams to simplify the
process of assigning roles to groups of people."