window: Get actual preferred action for AdwTabBar drop
Depends on libadwaita!849 (merged)
We are using a workaround to get the preferred action on the AdwTabBar extra drop, by setting data on the page within ::extra-drag-value. This hack doesn't account for the changes in preferred actions using the CTRL/SHIFT modifiers. Use the new adw api which gets the action directly from the GdkDrop.