Add developer option to reset taskbar search edu

This change allows you to view taskbar search edu again by tapping the
"Taskbar Search Edu" option in launcher developer options.

Fix: 350537725
Test: Go to developer options and reset the taskbar search edu. Check
that it shows up the next time an app is launched (and if the taskbar is pinned)
Flag: EXEMPT bugfix

Change-Id: I5a0e992ef3b3d62c62998a7bbe648e4598cdde54