Prevent multiple handle menus from opening.

Changes the handle menu logic such that if the open menu button is
clicked while the menu is currently open, it will close the existing
menu rather than make a second handle menu.

Bug: 277125646
Test: Manual; click the exposed corners of the open menu button while
handle menu is open. Confirm clicking handle menu pills is unaffected.

Change-Id: I230e1dcac2a338c41a7c74acb37e3c13b711f218