Fix missing edge extension for task fragment transition

The change info of task fragment doesn't have activity component.
Besides, because it is a layer effect, it only needs to set once
rather than each animation frame.

Bug: 322036393
Flag: com.android.graphics.libgui.flags.edge_extension_shader
Test: atest CtsWindowManagerDeviceAnimations:ActivityTransitionTests
Test: Switch settings page in folded screen,
      the edge should not be black.
Change-Id: Ic3b7888f126c3039d4be2bc9b706dfacfb224ecf