Review and refactor Permissions logic

[im-adithya]

Currently permissions editing is decided by request_methods in the query params, we should change this.

It can be based on individual params but again there should be a unified editing state (or not?)

[rolznz]

As part of this we should try fix this bug where you cannot see the custom amount:

I noticed, there's also a bug in the form if you set max_amount=100 on its own. You cannot see the set amount - just none of the boxes are selected.

From getAlby/nostr-wallet-connect-next#377 (comment)

[im-adithya]

Needs design input from @stackingsaunter

[rolznz]

Completed in #14 / #273