Use falsing manager on click to open user switcher

Fix issue that prevented user switcher from opening on tap

Bug: 186244907
Test: With config_keyguard_user_switch_opens_qs_details=true, check that
      tapping user icon opens the user switcher QS panel
Change-Id: Idf3c5154b87b13ea046a89f3fd2ed2a4fafcc28c