[SB] Don't do any custom touch handling in StatusBarWindowView.

StatusBarWindowView#dispatchTouchEvent was originally added for visual
immersive mode so that you could swipe down from the top of the screen
once to open the shade. However:

1) That user interaction still works even without the custom
dispatchTouchEvent logic.

2) That behavior is causing a problem with one-handed mode, where touching
a chip in the status bar doesn't do anything because StatusBarWindowView
is changing the `y` value of the MotionEvent to be `0`, which is outside
the region of the chip.

This CL just removes the custom StatusBarWindowView#dispatchTouchEvent
if a flag is on.

Bug: 391894499
Flag: com.android.systemui.status_bar_window_no_custom_touch
Test: In one-handed mode, have a status bar chip and touch it -> verify
the chip tap behavior occurs
Test: In visual immersive mode (e.g. viewing a photo), swipe down once
from the top of the screen -> verify the shade opens

Change-Id: I4d272aaad2f0c746b13491fa38fe603ef1d678f4