Actually working wasm storage clear

[v-kat]

The problem with wasm key deletion was also a shifting index. https://github.com/johanhelsing/bevy_pkv/blob/main/src/local_storage_store.rs#L96 was being called when the index was moved so any prior key deletions would mess up the index.
I switched to the much simpler clear api and made sure it was working on my bevy wasm project.

I should have tested #56 more.

[johanhelsing]

The downside with this is that it will delete any other things stored in local storage on the same domain.

[johanhelsing]

Also, could you explain what you mean by shifting index? I don't understand it

[v-kat]

The deletion loop starts with lower indexes which shifts the higher index keys as things are being deleted so not everything can be properly deleted as the indexes are off. I made a simpler change to fix the issue.

[johanhelsing]

Ah, nice catch. And fix 👍