Suppress visual indicator if cursor leaves original display

Addresses an issue where the desktop mode visual indicator (e.g., for
window snapping) would appear on the wrong monitor during cross-display
drag operations.

The root cause was that the indicator's visibility was tied solely to
the task's origin display, ignoring the cursor's actual current display.
This meant dragging a window to display B and hovering near an edge
could incorrectly trigger the indicator animation on display A where the
window was belonging to. See video: http://go/visual-indicator-xdisplay

As an initial fix, this commit prevents the indicator from showing at
all if the cursor is not on the display where the drag started. This
deliminates the confusing display on the incorrect monitor.

Bug: 389868684
Test: manual; atest DesktopTasksControllerTest DesktopModeVisualIndicatorTest
Flag: com.android.window.flags.enable_connected_displays_window_drag
Change-Id: Ifbf022ce6314fe700953285cc54b43da9adf6226