fix(abort-controller): Fix abort signal handling

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The problem was that the AbortController did not always trigger correctly or was not used correctly in all places. This meant that not all event listeners were always logged off, which resulted in messages being registered for callout responses that were no longer active. As a result, several responses were returned, for example, those of the callout currently being actively answered but also those of the previous callout. So this had nothing to do with multiple simultaneous chats, as I had initially assumed.

Changes

• The handling of the abort signal was not complete, this should now be fixed
• Setting a new state now always cancels the previous process using the abort signal

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@wpf500 This is the first time that I use the AbortController, so I would like to do a review because I don't know what good patterns look like here, this is actually a DOM standard, but Deno has implemented many of them, including the AbortController.