Remove non-functional NOTES shortcut

We will rely on ROLE_NOTES based bookmark to launch notes app
instead of dedicated system shortcut. With the shortcut
currently broken, we are removing the shortcut from system
shortcut logic.

Once ROLE_NOTES is available and added to default application
supported roles, we can add corresponding bookmark to the list
of app bookmarks (bookmarks.xml) and it should work.

Test: atest KeyGestureControllerTests
Test: atest KeyGestureEventTests
Bug: 390707077
Flag: EXEMPT bugfix
Change-Id: I9ff3509e0b04ec8127b6a6dcefd64ae7e5e2848d