* Add protocol `ContactResolving`
* Let the `IntentHandler` implement `ContactResolving` (#6203)
Nothing has changed about the implementation itself; this prepares
the separation of this logic into a dedicated unit.
* Prepare the separation of the contact resolver from the intents handler (#6203)
* Move the implementation of `ContactResolving` to a dedicated class (#6203)
* Move `ContactResolver` to a dedicated file (#6203)
* Prepare the separation of the `StartAudioCallIntentHandler` from `IntentsHandler` (#6203)
* Move the implementation of `INStartAudioCallIntentHandling` to a dedicated class (#6203)
* Prepare the separation of the `StartVideoCallIntentHandler` from `IntentsHandler` (#6203)
* Move the implementation of `INStartVideoCallIntentHandling` to a dedicated class (#6203)
* Prepare the separation of the `SendMessageIntentHandler` from `IntentsHandler` (#6203)
* Move the implementation of `INSendMessageIntentHandling` to a dedicated class (#6203)
* Remove unused property (#6203)
* Return `nil` if the requested intent cannot be handled (#6203)
* Initialize the intent handlers _after_ everything else is configured (#6203)
In `init()`, there might be some configuration being done that is
required for the handlers.
* Add changelog entry
* Move curly braces in Objective-C to dedicated lines
This ensures that the code follows the style that is present in other Objective-C files.
Co-authored-by: Doug <6060466+pixlwave@users.noreply.github.com>
* Inject the `ContactResolver` into the intent handlers during initialization
In #6365, @pixlwave pointed out that
> If the resolver ever gained a cache or stored properties it would
> help keep the memory usage down in the extension
* Prefer forward-declaration over import in Objective-C header files
Per @pixlwave, this helps prevent build failures:
> We had random cycle errors while building a while back and it was
> eventually solved by removing all imports of `GeneratedInterface-Swift.h`
> in every [Objective-C header] file.
Co-authored-by: Doug <6060466+pixlwave@users.noreply.github.com>
