Only trigger rebuild when relevant parts of the package manifest has been changed

[Hofer-Julian]

Now that https://github.com/prefix-dev/pixi/pull/3102 has been merged, every change to the package manifest will trigger a rebuild of the package.

What you actually want is a retrigger if something relevant to the build changed. In the long run, we'll want all of that stored in the lock file: https://github.com/prefix-dev/pixi/issues/2814#issuecomment-2639763828

As soon as that is implemented, we should rebuild every time the package data in the lock file changes

[wolfv]

Some experiments with additional_hash data here: https://github.com/prefix-dev/pixi/pull/3140