Don't cancel or commit predictive back on multi touch in 3-button-nav

Bug: 381054861
Test: Manual, i.e. verify that tapping the taskbar while predictive back is in progress does not cancel or commit it
Flag: com.android.window.flags.predictive_back_three_button_nav
Change-Id: I4117aca74216849519a0cabcbd3cb14f7fc5b38f
1 file changed