Add Livewire v4 support (#474)

* Add Livewire v4 support

* Update tests to use dynamic Livewire update endpoint

Livewire v4 changed the update endpoint path from /livewire/update
to a dynamic path. Use the livewireUpdateEndpoint() helper to
support both v3 and v4.

* Fix code styling

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Co-authored-by: joshhanley <882837+joshhanley@users.noreply.github.com>