Desks: Add keyboard shortcuts to switch active desks

Adds ACTION + CTRL + [ or ] as keyboard shortcuts to switch to the
previous or next desk. Desks are already ordered by creation time.

Flag: com.android.window.flags.keyboard_shortcuts_to_switch_desks
Bug: 389957556
Test: create multiple desks with adb command, then use
ACTION + CTRL + [ or ] to switch between them.

Change-Id: I15db75b7deb72b86d49714f1b5113cac13182aca