[feat] Being able to have the isolation hook be specific to a window

[matthme]

Describe the problem

Currently it doesn't seem to be possible to have the isolation hook behave differently for different windows, at least not on all platforms, since on Linux window.__TAURI_METADATA__ is undefined within the isolation hook (and I'm also not sure if it would be safe to use window.__TAURI_METADATA__ since it may be maliciously modified?).

Describe the solution you'd like

I would like to either be able to either have access to the window label in the isolation hook (ideally as part of the request object) or be able to define multiple, named isolation hooks in tauri.conf.json that I could then add to the window, e.g. through a method on the WindowBuilder.

Alternatives considered

I have not found any alternative that works on all platforms.

Additional context

No response