Accessor Semantics enforce incorrect usage patterns

[cleemullins]

All Versions.

In Botstate.ts there is a problem with how accessors are created:

   public createProperty<T = any>(name: string): StatePropertyAccessor<T> {
        if (this.properties.has(name)) { throw new Error(`BotState.createProperty(): a property named '${ name }' already exists.`); }
        const prop: BotStatePropertyAccessor<T> = new BotStatePropertyAccessor<T>(this, name);
        this.properties.set(name, prop);

        return prop;
    }

The dictionary that's used to gate the accessor creation is not needed. This prevents multiple accessors from being created, and forces bots to use global static accessors.

This signifigantly differs from the C# code, which allows these to be created at-will:

        public IStatePropertyAccessor<T> CreateProperty<T>(string name)
        {
            if (string.IsNullOrWhiteSpace(name))
            {
                throw new ArgumentNullException(nameof(name));
            }

            return new BotStatePropertyAccessor<T>(this, name);
        }

This difference bleeds into the samples in unexpected ways, and has caused @johnataylor to 💥 💥 💥. He's been 😾 as he tries to get the sidecar worked wrapped up.