Hide Shade Display Position developer option if shade flag disabled

Connected Displays shade work is no longer scheduled for 25Q3, so dev
option should be removed so if the flag is not enabled.

Bug: 414685067
Test: manually testing
Flag: com.android.systemui.shade_window_goes_around
Change-Id: Ieaf19ca4d24fd3bbc09427b7fc49dd78d04e71fd