libadwaita: upgrade 1.7.5 -> 1.7.6

libadwaita: upgrade 1.7.5 -> 1.7.6

Changes:
- AdwAlertDialog/AdwMessageDialog
  - Emit ::response when cancelled after calling choose()
- AdwDialog
  - Fix widget activation in window-backed dialogs
  - Fix set_focus() in window-backed dialogs
- AdwLayoutSlot
  - Error out if ID is not set
- AdwNavigationView
 - Defer swipe start to ::begin-swipe
- AdwTabOverview
  - Make button hitboxes larger
- AdwWrapLayout
  - Fix a memory leak
- Various fixes

Signed-off-by: Simone Weiß <simone.p.weiss@posteo.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>