[Feature] Serializable data function for invoking machines (string conditions)

[camsloanftc]

Following a chat with @Andarist in the discord, it was recommended to add a feature request for serialized data functions on invoked services in the same way that it is possible to do this with guards, actions, and activities.

          scrolling: {
            invoke: {
              src: 'scrollMachine',
              data: {
                // We would be able to do this
                scrollTarget: 'getScrollTarget',

                // Instead of this
                scrollTarget: (context: TourCtx, event: TourEvent) => {  ...etc      },
              },
          },

I heard there may be another issue related to this but after looking a bit through discussions and issues, I was unable to find anything.