🐛 Enabled morphing @event handlers

[ekwoka]

fixes #3493

This PR:

• when needing to set @event attributes on elements during morph, transforms them into properly prefixed x-on: attributes instead
• Tests the above behavior

[joshhanley]

@ekwoka in Livewire, we actually monkey patch the setAttribute method to allow @ symbols, see here https://github.com/livewire/livewire/blob/019b1e69d8cd8c7e749eba7a38e4fa69ecbc8f74/js/index.js#L142-L163

We're now using Alpine Morph for Livewire V3 and currently we're also monkey patching it there too.
I wonder whether it's worth adding something like that into the morph plugin instead?

[ekwoka]

It would make sense to have it live in Alpine morph. I'd probably not go with the monkey patching native behaviors though.

[calebporzio]

I already monkey patch .setAttribute to allow "@" symbols in Livewire so I'm pulling that over into Alpine to make this work. I scrapped your implementation, but kept your test. Thanks!