Fix reference to StimulusReflex::VersionMismatchError (#665)

# Bug fix

## Description

This reference to `StimulusReflex::Reflex::VersionMismatchError` in
`StimulusReflex::Channel` is using an old namespace that was changed
recently to `StimulusReflex::VersionMismatchError`.

## Why should this be added

Fixes #664 reported by @obie, additional discussion here:
https://discord.com/channels/629472241427415060/733725826411135107/1113306088796864615

## Checklist

- [x] My code follows the style guidelines of this project
- [x] Checks (StandardRB & Prettier-Standard) are passing

---------

Co-authored-by: Marco Roth <[email protected]>

app/channels/stimulus_reflex/channel.rb

@@ -27,7 +27,7 @@ def receive(data)
           reflex.logger&.error error_message
           reflex.broadcast_error data: data, error: "#{exception} #{exception.backtrace.first.split(":in ")[0] if Rails.env.development?}"
         else
-          unless exception.is_a?(StimulusReflex::Reflex::VersionMismatchError)
+          unless exception.is_a?(StimulusReflex::VersionMismatchError)
             StimulusReflex.config.logger.error error_message
           end