Can't paste image from clipboard on gnome 49

I've copied an image to the clipboard, LibreSprite Flatpak won't allow me to paste it in. The create sprite dialogue also doesn't suggest the image dimensions from clipboard.

### System
󱋩  bazzite-gnome-nvidia:stable 
󰣛  Bazzite
  Linux 6.17.7-ba29.fc43.x86_64
󰅐  16 hours, 23 mins

󰻠  Intel(R) Core(TM) i7 K 875 (8) @ 3.51 GHz
󰍛  NVIDIA GeForce GTX 960 [Discrete]
  4.79 GiB / 15.60 GiB (31%)
  136.80 GiB / 231.88 GiB (59%) - btrfs
󰍹  3440x1440 @ 1.25x in 34", 165 Hz [External]
󰖺  Mouse passthrough (absolute)

󰕮  GNOME 49.1
  Mutter (Wayland)
  bash 5.3.0
  Ptyxis 49.3
󰏖  2544 (rpm), 82 (flatpak-system), 27 (flatpak-user), 39 (brew), 1 (brew-cask)

Start by reproducing the clipboard paste and create-sprite dimension behavior in the LibreSprite Flatpak on GNOME 49 with Wayland. Compare both workflows to determine whether the failure is in the application or Flatpak integration; done means an image can be pasted and its clipboard dimensions populate the create-sprite dialog.

Written by the indexing model from the issue text.