feat: `shorebird release` should save off build arguments and `shorebird patch` should use them

[eseidel]

Right now it's possible to pass one set of --dart-defines when releasing and a different one when patching.

Maybe that's a feature? But it also feels like maybe something we should automatically match for you (or at least offer to?) when patching. Otherwise you could accidentally end up with a much larger patch than you expect.