Crop snapshot icons for Manage Windows menu.

Crops the provided task snapshot bitmaps to match the aspect ratio of
the icon buttons in the Manage Windows menu to prevent stretching the
bitmaps when they are particularly wide or tall.

Bug: 337915660
Bug: 372299112
Test: Manual
Flag: com.android.window.flags.enable_desktop_windowing_multi_instance_features
Change-Id: I15880d31328d547c547411449418d30602a98d6f