message: fix package preview not using correct package
diff: <app-game-package-card
  :game="game"
  :sellable="previewSellable"
  - :package="package"
  + :package="previewPackage"
  :releases="previewPackage ? previewPackage._releases : null"
  :builds="previewPackage ? previewPackage._builds : null"
  />
  