[store] Absolute vs. relative paths to the same store file are cached separately #984

Came across an interesting edge case today in the store plugin. If I create a store in JS like this:

const store = new Store(appDataDir() + "config.file")

and I try to access it from Rust like this:

let stores = app.state::<StoreCollection<Wry>>();
let path = PathBuf::from("config.file");

with_store(app_handle, stores, path, |store| store.insert("a".to_string(), json!("b")))

these will load from and save to the same file on the filesystem (thanks to https://github.com/tauri-apps/plugins-workspace/blob/v1/plugins/store/src/store.rs#L179), but they'll be cached separately because with_store just uses the key you give it (which in this case is an absolute path in JS and a relative path in Rust) - the line in question is here: https://github.com/tauri-apps/plugins-workspace/blob/v1/plugins/store/src/lib.rs#L57.

Since these two paths point to the same store file and load from/save to the same file, it feels to me like with_store should key on the absolute path constructed by load and save instead of just whatever the caller gives it.

Happy to throw together a quick PR in this direction if we think it makes sense!