Fix launcher holds a surfaceController

When the dark night mode switch is triggered,systemui calls binder
to the onNavigationBarSurface method in the launcher and applies the
surfaceController.
Keep switching,you will keep applying,resulting in more surface
objects. The behaviour would cause that SurfaceFlinger couldn't
remove the unnecessary navigationbar layers timely and the
navigationbar layer would leak in SF.

Actively release the SC after using the SC in the launcher.

Bug: 317336417
Test: 1.Launch the settings app
      2.Click Display menu
      3.click the dark theme menu multiple times
      4.Check whether the surfaceController is released
      adb shell "ls -l/proc/904/fd|wc -l"

Change-Id: Ic449de9dbe0c52e0053be91e67ee9081a574581b